refactor GtGenerator
fix method parameter
GtGenerator.InitContext(GtParserContext) => GtGenerator.InitContext(GtNameSpace)
rename field: GtSourceGenerator.VisitingBuilder => CurrentBuilder
remove old comment
added GtNodeVisitor
refactor GtNode.Accept(GtGenerator) => GtNode.Accept(GtNodeVisitor)
Merge branch 'NewParserLibrary' of github.com:GreenTeaScript/GreenTeaScript into NewParserLibrary

Conflicts:
	src/parser/GtGenerator.java
	src/parser/ast/GtAndNode.java
	src/parser/ast/GtBooleanNode.java
	src/parser/ast/GtCastNode.java
	src/parser/ast/GtErrorNode.java
	src/parser/ast/GtFloatNode.java
	src/parser/ast/GtGroupNode.java
	src/parser/ast/GtIntNode.java
	src/parser/ast/GtNode.java
	src/parser/ast/GtNullNode.java
	src/parser/ast/GtOrNode.java
	src/parser/ast/GtStringNode.java
	src/parser/ast/GtTrinaryNode.java
	src/parser/ast/GtTypeNode.java
	src/parser/ast/GtUnaryNode.java
	src/parser/ast2/GtGetIndexNode.java
	src/parser/ast2/GtInstanceOfNode.java
	src/parser/ast2/GtMapLiteralNode.java
	src/parser/ast2/GtRegexNode.java
	src/parser/ast2/GtSetIndexNode.java