add Generator API
add header file
fix new GtMethod()
fix TypeNull type-checker
fix AddOverloadedMethod()
fix c interface
bug fixed at TypeApply
adding test AlwaysFailedTest
Merge branch 'master' of github.com:GreenTeaScript/GreenTeaScript
adding SubClassTest
bugs fixed at test code
remove cast
Merge branch 'master' of github.com:GreenTeaScript/GreenTeaScript
update command option
refactoring PythonGenerator
fix Let/And/Or
split playground_dev from playground
Merge branch 'master' of https://github.com/GreenTeaScript/GreenTeaScript
fix playground index.html
using PolyFunc in TypeApply