Add company-mode backend
- Includes support for async candidate retrieval
- Function calls now expanded as yasnippet templates
- Configured as the new default using ensime-completion-style

Add an Emacs 24 CAP backend.

Two new dependencies:
- yasnippet
- company-mode
Merge pull request #63 from aemoncannon/company

Add company-mode backend (resolves #467)
Add travis badge to readme.
Fixes a few failing tests. Adds travis misc. As of this PR the
emacs suite is running and passing on travis.
Merge pull request #65 from aemoncannon/test-fixes

Fixes for emacs integration tests (resolves #710)
Fix #688 : jump to correct line from stacktrace
Merge pull request #67 from edani/stack-688

Jump to correct line from stacktrace