adding GitHub Enterprise variables to Boxen config
adding docs for Github Enterprise users
Merge pull request #274 from mdelagralfo/github-enterprise

Github enterprise config and docs
Fix the line numbers for the variable highlighting.
Merge pull request #281 from sclm/patch-1

Fix the line numbers for the variable highlighting in docs
Fix typo: 1.0.5 -> 1.1.0

Code says `github "java",     "1.1.0"`, but documentation says "1.0.5", so I fixed it.
Merge pull request #283 from adamnbowen/patch-1

Fix typo: 1.0.5 -> 1.1.0
Merge remote-tracking branch 'upstream/master'