fix Spyder block/hang (iss 151 & 183) and wrong dotted line char (iss 186)

Author: DanielGoldfarb

src/mplfinance/_utils.py

@@ -274,7 +274,7 @@ def _valid_lines_kwargs():
                          a limited set of allowed values) may also validate that the
                          kwarg value is one of the allowed values.
     '''
-    valid_linestyles = ['-','solid','--','dashed','-.','dashdot','.','dotted',None,' ','']
+    valid_linestyles = ['-','solid','--','dashed','-.','dashdot',':','dotted',None,' ','']
     vkwargs = {
         'hlines'    : { 'Default'     : None,
                         'Validator'   : _bypass_kwarg_validation },

src/mplfinance/plotting.py

@@ -150,7 +150,7 @@ def _valid_plot_kwargs():
         'savefig'                   : { 'Default'     : None, 
                                         'Validator'   : lambda value: isinstance(value,dict) or isinstance(value,str) or isinstance(value, io.BytesIO) },
 
-        'block'                     : { 'Default'     : True, 
+        'block'                     : { 'Default'     : None, 
                                         'Validator'   : lambda value: isinstance(value,bool) },
 
         'returnfig'                 : { 'Default'     : False,