CppParser: fix warning about RawCommentKind

Fix the following warning by renaming RawComment::RawCommentKind to
Kind.

In file included from ../../../src/CppParser/AST.cpp:8:0:
../../../src/CppParser/AST.h:780:20: warning: declaration of ‘CppSharp::CppParser::AST::RawCommentKind CppSharp::CppParser::AST::RawComment::RawCommentKind’ [-fpermissive]
     RawCommentKind RawCommentKind;
                    ^
../../../src/CppParser/AST.h:765:13: warning: changes meaning of ‘RawCommentKind’ from ‘enum class CppSharp::CppParser::AST::RawCommentKind’ [-fpermissive]
 enum struct RawCommentKind
             ^

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@iki.fi>
CppParser: fix warning about FullComment

Fix the following warning by renaming RawComment::FullComment to
FullCommentBlock.

In file included from ../../../src/CppParser/AST.cpp:8:0:
../../../src/CppParser/AST.h:783:18: warning: declaration of ‘CppSharp::CppParser::AST::FullComment* CppSharp::CppParser::AST::RawComment::FullComment’ [-fpermissive]
     FullComment* FullComment;
                  ^
../../../src/CppParser/AST.h:760:15: warning: changes meaning of ‘FullComment’ from ‘struct CppSharp::CppParser::AST::FullComment’ [-fpermissive]
 struct CS_API FullComment : public Comment
               ^

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@iki.fi>
CppParser: fix warning about Parser

Fix the following warning by renaming ParserResult::Parser to
CodeParser.

In file included from ../../../src/CppParser/Parser.h:16:0,
                 from ../../../src/CppParser/Comments.cpp:8:
../../../src/CppParser/CppParser.h:86:13: warning: declaration of ‘CppSharp::CppParser::Parser* CppSharp::CppParser::ParserResult::Parser’ [-fpermissive]
     Parser* Parser;
             ^
../../../src/CppParser/CppParser.h:73:8: warning: changes meaning of ‘Parser’ from ‘struct CppSharp::CppParser::Parser’ [-fpermissive]
 struct Parser;
        ^

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@iki.fi>
build: remove -fpermissive from non-VS builds

Now that the warnings have been fixed, we no longer need -fpermissive to
compile CppParser with gcc.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@iki.fi>