Added support for both major and minor version matching.

Added a bit more of complexity since we can now match functions by major version only, or major and minor version. This will improve arithmetic comparisons sometimes required when choosing which piece of code gets executed.
Merge branch 'develop' of github.com:saltstack/salt-bootstrap into develop
Adapted FreeBSD functions to the recently version matching. Refs #37.

Added `DISTRO_MAJOR_VERSION` to `BS_PACKAGESITE` as suggested by @geoffgarside. Refs #47.
Merge pull request #49 from s0undt3ch/develop

Major and Minor version matching