Adds documentation about GHE_EXTRA_SSH_OPTS in example config file
Link to Administrator's Guide for migrating to v2.0 docs
Note explicitly that GHE v2.0 is supported
Misc cleanup -s note in README
Merge pull request #80 from veloandy/document_GHE_EXTRA_SSH_OPTS

Adds documentation about GHE_EXTRA_SSH_OPTS in example config file
Merge pull request #81 from github/readme-2.0-notes

Light README updates for GitHub Enterprise v2.0