Fixing holtWintersAberration error when upper and lower bands have None values.
Composer: create from URL

New function in the composer toolbar to create a graph from a URL.
This is based entirely off of @obfuscurity Stupid Graphite Tips
https://speakerdeck.com/obfuscurity/stupid-graphite-tips?slide=12

Icon is Creative Commons:
https://www.iconfinder.com/icons/49529/link_url_icon

Conflicts:
	webapp/content/js/composer_widgets.js
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.
Check length of time format for ':' conditional in attime.py

This fixes https://github.com/graphite-project/graphite-web/issues/511 and allows you to use time format like '00:00' again.
Remove sys.path manipulation
Sort by name
first working python only lowess implementation... but it's slow
modified to have shorter inner loop and use scipy instead of numpy
only process every 15 and the last 5 data points
added lowess smoothing via cython version (cylowess) of the function
1) cylowess is now optional, 2) at lowess runtime check for cylowess, 3) if found use it otherwise use pure python, 4) pure python performance improved by new delta calc and skipping data for larger data sets
Integrate functions_test to the test suite
Merge branch 'master' into functions-tests
Fix a failing test by providing proper start/end/step values
Merge branch 'master' into fix/path
Update path to manage.py
Merge pull request #543 from brutasse/functions-tests

Integrate functions_test to the test suite
Merge pull request #498 from justino/m_composer_from_url

Composer: create from URL
Merge pull request #538 from steveakers/master

Adding lowess (locally weighted scatterplot smoothing) via cylowess, a cython port of the lowess function.