Bitbucket integration

Hi,
Found your plugin and I think it's great. It happens that I work with Bitbucket as SCM and this plugin didn't have that integration.... until now.

I did the integration and also some refactoring to be able to create a link to the viewimage action. 

Please review the code and (i hope that) add it to you master branch. By doing this I'll be able to use your plugin as submodule in my projects.

Best regards,
Marcos