Now using protected branches

[dcousens]

Master is now protected.

See https://github.com/blog/2051-protected-branches-and-required-status-checks for more information.

TL;DR, all tests must pass before we can merge, force pushing is also disabled [for master].

edit: you can see protected logo on the https://github.com/bitcoinjs/bitcoinjs-lib/branches/all page

[weilu]

👍

[dcousens]

Enabled travis-ci as a status update that must pass, for some reason that wasn't the default.

[dcousens]

Stopped TRAVIS from testing merges since the current branch protection policy stops non-fast forward merges anyway.
It now solely tests the pull request alone, and that PR must be rebased on HEAD to be merged.

[dcousens]

Merged #499 and #502 without status checks.
Now re-enabled.