Implemented Update() function for graphite backend
Update list items and count handling.
Clean up and refactor graph creation handling.
Save color state in options to prevent its loss.
Fix name fields update when creating graphs.
Fix expanded series color loss.
Update HTML tags options handing.

 * Prevent empty options printing.
 * Remove unneeded range option in HTML template.
 * Fix HTML attribute split.
Refactor serie and group items value access.
Fix various problem with graph creation.

 * Make item reorder skipping linked elements.
 * Fix error with missing serie options.
 * Remove unused variables.
Make series appended at position.
Add series positions handling in graph creation.
Reformat jshint unused comments.
Update messages for empty lists.
Fix collection parent-children relation loss.
Reset field value when input is empyied.
Move group expansion from catalog to library.
Add pattern preview in group creation.
Fix graph drawing problem with expanded series.

 * Add handling for null item in backend requests.
 * Propagate expanded serie name in stack pane.
Fix NONE group with mutiple series missing plots.
Rewrite backend sources and metrics handling.

 * Move RRD-specific fields to RRD backend.
 * Add channel for sources and metrics registration.