Add empty build folder for Hamming

Rake compilation stops because empty “build” folder is not present.
Adding an empty folder to silence that error.

Using a .gitignore file to keep folder in version control.
Remove Rake dependency on test/support folder

Rake compilation was stopping because this empty folder was not
included in version control.
Change source of vendor files to common xc dir
Move vendor folder to xc directory
Merge pull request #2 from sunzenshen/ceedling_share

Move Ceedling vendor files to common location