Graph: series override dropdown menu select did not work after recent commit that added typeahead to this dropdown

Help: added help modal, accessed by shortcut '?', the help modal only contains a list of all shortcuts right now but will be extended in the future, #952

Graph: fill below to series override option not automatically adds lines=false, as overrides, if you want lines just for the fill below series just remove the overrides, #940

Graph: New series style override option 'Fill below to', useful to visualize max & min as shadow for the mean, #940

InfluxDB: series lookup & typeahead is now handled by influxdb list series regex queries, Closes #888

Tech: removed jquery-ui and jquiery-ui-angular-drag-drop, replaced with native drag drop for angular, saved ~50kb in js libs, much cleaner & simpler usage, Also changed some behavior for drag drop, now panels are replaced when droped on (switch places), Closes #920

Graph: fix for bars not displaying, caused by change in recent commit, added unit test so it does not happen again

Speed search result parsing

Graph: fixed value formating for tooltip, need original data. flotcharts copys the data, so changes to value formats func after plot call does not affect the plot.getData() series

second parameter of groupByNode() should be 0 indexed

Fix #901: correct positioning for multiple highlighted stacked and staircase points

Reuse ElasticSearch hits length via hits.total and cache it rahter than calculation length every iteration.

New backend call to each keydown may hit the back-end performance.
500ms is reasonable delay to avoid too many requests while user is
typing a search query

Inline styles slow down rendering proportionally to containers number