Added some saftey checks to CacheEntry password functions for NULL/zero-length passwords.
Added CacheUtilGlob method for listing files using glob expressions.
Fixed some const issues in CachePolicyNewForUser().
Added .gitignore file which ignores most autotools-generated files.
Updated EXTRA_DIST values in Makefiles.
Added the actual PAM module with pam_sm_* functions.
Fixed memory leak in CacheTestSetMockTime()
Add release tarball filename to .gitignore
Updated contributor docs with minor fixes and more info about testing
Use strlen instead of an int when removing prefix from a string
Added checks for repeated arguments to the PAM module
Merge pull request #3 from google/vonhollen-dev

Added actual PAM module, updated docs, and made a few minor fixes