modified TypeConst
Revert "modified TypeConst"

This reverts commit ab60d13d4124ad7e74f227cc8307e65938a38a69.
fix JS Generator
make it more restricted
Merge branch 'master' of https://github.com/GreenTeaScript/GreenTeaScript
support stringliteral and letnode
Merge branch 'master' of github.com:GreenTeaScript/GreenTeaScript into GreenTeaScript
fix conflict