Better cacerts handling

- setup will not compress the .egg which prevented cacerts access
- new cacerts attribute in the Shotgun constructor
- git will now ignore (.gitignore) structures created by easy_install
Merge pull request #36 from shotgunsoftware/18171_better_cacerts_handling

Better cacerts handling
Version bump to 3.0.12

- Updated version to 3.0.12 in preparation of next release
- Updated README.mdown