StringBuilder: added void* function
codegen: dont add package prefix for ansi C libs
codegen: add package prefix for usertypes
codegen: prefix types as well
codegen: use correct name for functions
analyser: check if package was aliased
analyser: better errog msg when forgetting 'func' keyword
codegen: set correct LLVM linkage for functions
analyser: check if main function is public
examples: fixed non-public main()
analyser: checking for main() in targets