Add versioning info to Panic library.

This commit adds versioning info to the panic handler library.
Fix the test code for Thread_Utils

The Thread_Utils code in the inital commit is an old version.
So I'm replacing it with the correct one.

This commit replaces the Thread_Utils test code with the correct
version.
Add gitignore file

Adds a gitingore file.
Forgot CoreMain header file.

This commit adds the missing CoreMain header file.
Replace Doxyfile with correct version.

This commit replaces the Doxyfile with the correct version.
Replace Thread_Utils with correct version.

This commit replaces the Thread_Utils code with the correct version.
The inital commit had a non-functional older version of Thread_Utils
that I forgot about.

(That's what happens when you use two different systems to program on.)