Use @dev versions of dependencies during development.
Solving failed tests on Travis

1. use Sahi v44 to solve problems with using latest Firefox v25+.
2. grab Sahi console output and display it after tests have failed
3. update Firefox location in Sahi config
Merge pull request #18 from aik099/use-dev-mink-version-in-development-fix

Use @dev versions of dependencies during development