Fix commented code
Group token text and type in new class token
Refactor tokenizer in fashion of an iterator of tokens
Add abc::mstr::clear() to simplify truncating mutable strings
Use “relational operator” consistently instead of “comparison operator”
Add unit test for abc::mstr::clear()
Add new struct abc::detail::raw_vextr_impl_data defining all data members of raw_vextr_impl_base
Add abc::istr::empty static constant
Make abc::istr::empty a public symbol
Use abc::istr::empty instead of ABC_SL(""): prettier and faster
Add basic differentiation between punctuation that composes operators
Return specific token types for non-specific punctuation
Load the first token upon construction
Simplify token_iterator end
Add missing inline qualifier