removed BuildNumber

From what I have seen, mainly in CJ's quest to properly use BuildCraft as a dependency.. the BuildNumber has been a pain. People have to remember it, or have to be told by someone who has access to the jenkins what the buildnumber of a given version of BC has. The only real advantage of a build number imho is for in-dev builds that are released as betas or such. Since buildcraft does not release in this fassion, I think the build number should be removed entirely, and perhaps replaced by a commit-hash and branchName for the development builds.

Apperantly the buildnumbers were used before as an update checker, however that has not been updated.. and thats something else we would need to tackle.. in a different way...
I am leaving this versionChecker code intact for the time bieng..

TLDR:
 * build numbers arnt needed, im removing them.
 * lemme know if I should implement a branch name and commit hash appendage for builds not coming from the master branch.

This PR was lazily made from the github web UI, lemme know if you want me to squash it.