Bump to Sass 3.4 and Compass 1.0 (gemspec + Gemfile), updated tests control output

This is a swifter duplicate of #72.

Test output:

```
$ bundle list | grep 'sass\|compass'
  * compass (1.0.1)
  * compass-core (1.0.1)
  * compass-import-once (1.0.5)
  * sass (3.4.0)


$ bundle exec ruby .unit_tests.rb
...
14 tests, 14 assertions, 0 failures, 0 errors, 0 skips
ruby -v: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
```