Fix memory leaks

Make sure that we have no leaks when we call compiler with trivial flags like -help, -C, -prsc, etc. I have verified this using valgrind --leak-check=full ./sac2c_d <flags>.

added 72 commits

• b884c771...8e91765e - 63 commits from branch sac-group:develop
• eb87e0fb - Trivial memory leaks mainly from using STRcpy-like functions.
• 74310801 - For Christ's Sake!
• 7afd352c - Cleanup globals after printing `-help`.
• 47ea4565 - Free symbol names in the parser hash table.
• 205962ab - Free the original string at the end of tokenization.
• a9f5fa73 - Extend the table of filenames rather than create from scratch.
• 0777eefe - Free globals in CTIexit.
• 806b0695 - Use CTIexit in options.c.
• 50749d4e - Test sanity of a few basic options.

Compare with previous version

merged

mentioned in commit 3f289c91