Fixed most integration tests

The ensime-debug test still needs to be fixed.
Merge pull request #62 from edani/fix-more-tests

Fixed most integration tests
Cache the connection
Merge pull request #64 from aemoncannon/optimize-source-mapping

Cache the current connection at each buffer, to avoid repeated, costly lookups.
Add company-mode backend
 - Includes upport 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