Github triggering should be branch aware

It would be interesting of having a feature to a webhook where Bamboo identifies what is the latest commit made and to it branch and run a build based on those information.

At moment, users require to add at least one entry as a webhook to build a particular branch in Bamboo. Due to that, every time a new Branch is created and or deleted, users are required to add/remove manually webhook entries.

1. The "main" branch gets triggered via a web hook from Github
2. Automatically build branches is enabled.

With this setup, there's no way for the trigger that cause the branches that have a change to be built. There's no way for GitHub to know what the plan keys are for each branch.

Doing a polling trigger means waiting for the poll interval to elapse; and even at 30 seconds, in our setup, this is too long, as we're using the CI server as part of development testing.

Jenkins has no problem doing this – it's able to build whatever branches are changed via a trigger notification correctly. We'll probably stick with Jenkins until Bamboo can do this.