Print error messages when data type errors in ST expressions are detected.

Include (again!) the declaration of standard functions (incorrectly removed -again- in previous commit)

Add support for '**' (power) operator in ST expressions

Some more comments on how to build, and correcting name of README.build file.

Include the declaration of standard functions (incorrectly removed in previous commit)

Merging with Laurent's repository.

Fixing automake configuration to work properly with flex and bison.

Building compiler with autoconf. Thanks go to Matteo of sirius-es.it

Support for semantic verification of calls to standard functions.
Removing files no longer required.

Support for semantic verification of calls to standard function calls.
Adding missing files in previous commit.

Support for semantic verification of calls to standard functions.
This commit makes a fundamental change in the way standard functions are handled by the compiler.

Fixing exponentiation used with symbol **

Fix bugs in exponentiation

Fix case statement in ST, adding support for enumerated types

Adding BYTE operators visit functions in inlinefcall