ngrok 1.6 (new formula)

This pr adds a brew for ngrok[1], a tool that allows you to securely expose
a local web server to the internet and capture all traffic for detailed
inspection and replay. The formula is Go-based and depends on Go,
Bazaar, and Mercurial.

This formula is a new from-source PR as requested by @mikemcquaid on
issue 20839 - essentially a resubmission of 23732 which has an
unresponsive author.

[1]: https://ngrok.com
ngrok: add 1.6 bottle.

Closes #27598.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
nvm 0.6.1

Closes #29042.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Merge pull request #1 from Homebrew/master

Solr 4.8.0