Fixing holtWintersAberration error when upper and lower bands have None values.
Adding the ability to reorder metrics via the composer

This adds a new button menu on the right panel and new menu to the target context menu.
Gives the ability to select X targets, and move them in unison up and down.
If you select exactly 2 targets, then you can also do an in place swap.
Make sure timeShift(...) doesn't crash for non-existing series, fixes graphite-web issue #217.
Remove sys.path manipulation
Merge branch 'master' into fix/path
Update path to manage.py
Merge pull request #505 from zaptm/master

Make sure timeShift(...) doesn't crash for non-existing series
Merge pull request #502 from justino/sortable_metrics

Adding the ability to reorder metrics via the composer
Merge pull request #517 from brutasse/fix/path

Remove sys.path manipulation
Merge pull request #547 from aaronfc/master

Fixing holtWintersAberration error when upper and lower bands have None ...
Added aggregateLine function.
Fleshing out the docstring and correcting punctuation.
Merge pull request #549 from red5studios/aggregateLine

Added aggregateLine function.
Fix IndentationError
Merge pull request #554 from lukemarsden/fix-indent-error

Fix IndentationError in check-dependencies.py