Merge PySPConfigBlock back into pyutilib.misc.config

[jsiirola]

In an effort to simplify / standardize configuration / options in Pyomo, we should ensure that we only use a single configuration management system. The customizations / overrides in PySPConfigBlock and PySPConfigValue should be reviewed and, if appropriate, merged into pyutilib.misc.config. PySP should then directly use the pyutilib.misc.config system.

[ghackebeil]

@jsiirola: There are still a few methods on PySPConfigBlock that add or change functionality from ConfigBlock. Two of those could be move off of the class and just be made helper functions that I use in PySP (or potentially elsewhere). However, there are three other methods that make some pretty fundamental differences in behavior. The following example should summarize what those differences are:

from pyomo.pysp.util.config import PySPConfigBlock
from pyutilib.misc.config import ConfigBlock

#                                                                                                                                                                                                                
# Overriding __setattr__                                                                                                                                                                                         
#                                                                                                                                                                                                                
print("")
b = PySPConfigBlock(implicit=True)
b.entry_1 = True
print('entry_1' in b) # -> True                                                                                                                                                                                  
print('entry 1' in b) # -> False                                                                                                                                                                                 

b = ConfigBlock(implicit=True)
b.entry_1 = True
print('entry_1' in b) # -> False                                                                                                                                                                                 
print('entry 1' in b) # -> True                                                                                                                                                                                  

#                                                                                                                                                                                                                
# Adding __delattr__                                                                                                                                                                                             
#                                                                                                                                                                                                                
print("")
b = PySPConfigBlock(implicit=True)
b.entry = True
print('entry' in b) # -> True                                                                                                                                                                                    
del b.entry
print('entry' in b) # -> False                                                                                                                                                                                   

b = ConfigBlock(implicit=True)
b.entry = True
print('entry' in b) # -> True                                                                                                                                                                                    
try:
    del b.entry # -> AttributeError                                                                                                                                                                              
except AttributeError:
    print("Caught AttributeError on 'del b.entry'")

#                                                                                                                                                                                                                
# Override add                                                                                                                                                                                                   
#                                                                                                                                                                                                                
print("")
b = PySPConfigBlock(implicit=True)
b.entry = True
print(list(v.name() for v in b.user_values())) # -> ['entry']                                                                                                                                                    

b = ConfigBlock(implicit=True)
b.entry = True
print(list(v.name() for v in b.user_values())) # -> ['']