add files for SMLSharpGenenator
add built-in method for SMLSharp in lib/common.libbun
implement Visit(Boolean|Int|Float|String)Node,
VisitBlockNode, VisitReturnNode and VisitFunctionNode
Merge pull request #79 from Kouhei-Moriya/SMLSharpGen

add files for SMLSharpGenenator
refactoring python parser

refactoring if pattern

fix operator

fix while test

add self assign

move whilepattern

add test and stub
Merge pull request #80 from nikuuchi/python

refactoring python parser