implement translate for CommaExpression and CastExpression
remove trailing blanks
fix bug when creating struct_declaration
use a tempTypeIDTable instead of typeIDTable during lexing and parsing
modify StructType and UnionType
rename *Membto *Field*
implement getIRType and getFieldPointerByName for StructType and UnionType
implement getPointer for several kinds of expression, implement * and & unary expression
implement translate and setValue for InstanceFieldAccessExpression and PointerFieldAccessExpression
implement translate for TypeDeclarator
implement 'getPointer' 'setValue' and 'translate' for ArrayAccessExpression