Added first chunk of code for the lexer.
Added items to libs TODO. Also added unions (?) to main TODO.
The question is whether unions will take the place of dynamic
variables in LFyre. It is a question I have to answer soon.
Added a string to lexer (to hold previous chars). Also added
a comment in main.cpp to get out of standard error checking.
Added errors to main TODO list (in docs folder).
Added an error statement for when the compiler can't open a file.