Restructuration

Big changes regarding the whole structure, where the Compilerwork can be
done properly:
Parser completely included + Stack,Location,position.
Changes in particular:
- rename of the outputfile from gramatica.tab.c to gramatica.c (easier
reading ;-))
-From "Expression.h" on we can create the objects for the abstract
syntax-tree
- The "Driver.h" conntect the Lexer, parser and variable tables an so on
- "main" created, it is better, with some intelligence for reading
files, streaminput, etc
New files for gramatica, tokens :-)

was necessary in order for the strcuture-changes