Revert "Revert "Bug 717062 - Root preferences branch for simple-prefs needs to be configurable r=@erikvold""

This reverts commit 3784678ed07b074295bacd7d67ca259b043c0b8c.
Bug 717062 exposing require("sdk/self").preferencesBranch
Bug 903032 removing docs related python
Merge branch 'master' of github.com:mozilla/addon-sdk into 717062v2
Bug 717062 Adding regression test
bug 958609 - add note about Python 2.7.6 to README

and update documentation links to MDN
bug 958609 - don't imply future fixes
Merge pull request #1352 from zombie/958609-python-276

bug 958609 - add note about Python 2.7.6 to README
Merge branch 'master' of github.com:mozilla/addon-sdk into 717062v2

Conflicts:
	lib/sdk/simple-prefs.js
Merge pull request #1211 from erikvold/717062v2

Bug 717062 Redux - Root preferences branch for simple-prefs is now configurable r=@Mossop
bug 961247 - require method/core relatively
Merge pull request #1354 from zombie/961247-method-require

Fix bug 961247 - require method/core relatively, r=@jsantell
Bug 882910 - toolbarbutton's icon doesn't have a max height

- Added `sdk-button` attribute to buttons created by SDK, in order to apply the style properly
Bug 961245 sdk/self makes less assumptions about loader options
Merge pull request #1357 from jsantell/961245-remove-assumptions-from-self

Fixes Bug 961245 sdk/self makes less assumptions about loader options, r=@erikvold
Merge pull request #1342 from erikvold/remove-doc-py

Bug 903032 removing docs related python r=@Mossop
Bug 903032 removing code for testing docs related python
Merge pull request #1360 from erikvold/903032p3

Bug 903032 removing code for testing docs which no longer exist in this repo r=@jsantell
Merge pull request #1359 from ZER0/max-height/882910

Bug 882910 - toolbarbutton's icon doesn't have a max height