Rename Type::invariantOf to immutableOf
Use operator[] instead of tdata()
[ConvToBool] Object::equals
[ConvToBool] Dsymbol::(isAnonymous|isforwardRef|isExport|isImportedSymbol)
[ConvToBool] Dsymbol::(isOverloadable|hasOverloads|needThis|hasPointers)
[ConvToBool] Dsymbol::(overloadInsert|oneMembers?)
[ConvToBool] Declaration::is(Delete|Dataseg|Threadlocal|Codeseg)
[ConvToBool] VarDeclaration::(isCTFE|canTakeAddressOf|needsAutoDtor)
[ConvToBool] FuncDeclaration::is(Win|Dll)?Main
[ConvToBool] FuncDeclaration::is(Abstract|Safe|Trusted) and ClassDeclaration::isAbstract
[ConvToBool] FuncDeclaration::is(Nested|VirtualMethod|Virtual|Final)
[ConvToBool] FuncDeclaration::add(Pre|Post)Invariant
[ConvToBool] TupleDeclaration::isexp
[ConvToBool] AliasDeclaration::inSemantic
[ConvToBool] FuncDeclaration::inferRetType
[ConvToBool] FuncDeclaration::(needsClosure|hasNestedFrameRefs)
[ConvToBool] FuncAliasDeclaration::hasOverloads and (Dsymbol|Symbol|DotVar|Delegate)Exp::hasOverloads
fix declaration comments
Merge pull request #2088 from 9rnsr/refactor_code

[Refactoring] code
Merge pull request #2089 from 9rnsr/refactor_bool

[Refactoring] int to bool