Added an option to the driver to just run the lexer over a program.

I am going to use this to test the lexer on *REAL* programs to robustify it. The
plan is to use netlib for this purpose.
Sorted includes in Parser.cpp.
Fixed flang cmake build.

The bug was that different libraries were not properly set up as dependencies of
each otherI did not notice the bug since I was the libraries separately manually
and did not do a full clean.