Corrected problem due to design flaw in Parser class;
Moved method definitions from parser.h to parser.cpp.
Explicited naming convention for macros;
Renamed function string_to to string_to_tuple in parser.cpp;
Added convention for mangling in mangling.txt;
Added structures that will be generated by the semantic analysis in ast.h
Corrected std::iterator_traits<position_iterator>::iterator_category to std::forward_iterator_tag
Added basic structure of symbols, operators and symbol table (for semantic analysis)