Update .travis.yml

Builds are still failing. Instead, we'll only use released versions for testing.

Update .travis.yml

Ugh.

Update .travis.yml
No need to manually get gocov
Coveralls.io recommends doing it this way instead.
Remove specific Go version and allow Travis to decide.
Ugh.
Builds are still failing. Instead, we'll only use released versions for testing.
Add package-scope Call function.
Update README.me
Fix badges