Examples fixes (#370)

* cherrypick this to apply onto master. TODO: Cherrypick.

* Added another tests: moose.Function controls reaction rates.

* Using MooseParser as a interface class.

* Use moose.element instead of moose.Clock.

* When x1 is set to hight, rescale diffLength. When diffLength is set too
low, rescale x1.

* Don't print time to initialize info in release.

* honour limit set by SparseMatrix. Max number of entries allowed is 20k.

Author: dilawar

builtins/CMakeLists.txt

@@ -51,7 +51,6 @@ set(SRCS
     Arith.cpp
     Group.cpp
     Mstring.cpp
-    # Func.cpp
     MooseParser.cpp
     Function.cpp
     Variable.cpp