Fix for search result list and double link to dashboard that caused navigation start recursion when unsaved changed dialog was displayed

UI improvements to search result list (larger click are for dashboard title link, plus UI look polish), Closes #709

custom date modal is still local time, Closes #277

the graphite parser / query editor bail and fallback to text edit mode.

Closes #703

some initial work on making it easy to add a custom datasource without modifing the original source, #701, #553

Drag drop binding expression watcher was expensive, removed watcher after first eval, seems to still work

Save dropdown and search bindings and scope is now not loaded on dashboard load, small performance improvement

Removed add-panel tab from row editor, only add panels from the row menu now, do not want to ways to do the same thing