add multifieldhistogram panel
rename chart directive to not conflict with histogram
remove bars, extend fields table, quesries->markers, improve default aliases
fix scale and derivative in multifieldhistogram
Include jquery.flot.stack* for using in multiple panels

When using multiple panels that use the stacked graphs
(e.g. histogram and multifieldhistogram) we need to inform
grunt-requirejs plugin that jquery.flot.stack* is one the
modules to prevent double-inclusion and then problems
in the histogram rendering.

See https://github.com/elasticsearch/kibana/pull/1296

NOTE: this change is needed for getting pull#1296 to work
properly but can be merged indipendently from it.
integral support for histogram panel
Add download option, supporting JSON and CSV formats
Stats panel: Make formats more flexible.

* Adds capability to change the formatting individually for modes.
  E.g. 'count' shouldn't be displayed in bytes, rather it should just
  be a natural number.
* Implementation: define individual formatting functions for each mode
  and patch up the angular template as needed.
* (Closes #1285.)

Signed-off-by: Joe MacMahon <joe.macmahon@cern.ch>
Merge pull request #1 from johann8384/v3.1.0-plus

V3.1.0 plus