tidy up branches on github

[aspark21]

It doesn't really make sense that the master branch is for older versions of Moodle while the MOODLE_27_STABLE branch is for 2.7-3.0+ - merge requests are being done against the wrong branches (e.g #30). I would suggest making the current master branch the 'MOODLE_26_STABLE' branch noting in the README that this is for 2.0-2.6 (which is not supported by HQ at all these days) and then making the current 'MOODLE_27_STABLE' branch the master one and noting in that branch's Readme that older versions are supported in the MOODLE_26_STABLE branch.

This would make it consistent with how all the other Moodle plugins manage branches for old/legacy moodle versions vs new moodle versions

[xow]

+1

[jleyva]

Yes, you are right. I'll try to fix this not only in this repo but in the rest too.

Sorry for not being very active here but I have to maintain this in my spare time.