compatibility with standard syntax definition in part of #include scopes
highlight line continuation as a keyword
fighting with regexps for macros: fix #4-related regression, proper handling of inline comments
make regexp for all inline comments possessive (* -> *+)
(MAJOR) rework macro parameters handling: complete CFG-level parsing
line continuation with a trailing space doesn't consume a newline now
(it is considered an error hence technically it is not a line continuation)
highlight a space after continuation differently:
do not mess with errors caused by broken continuation (if any),
after all, gcc and clang treat it as a warning, not an error