Fixes for issue #777

- Data updates for widgets on dashboards are now reduced in number of data to resoultion of graph
Fixes for issue #777

- Data for histogram now now reduced based on resolution of graph
Fixes for issue #777

- Dynamically added width to link from dashboard replaying query
Fixes for issue #777

- Resolution of histogram now depends on time range of search, making it more reasonable
Fix for issue #862: Wrong encoding of query when updating histogram solution is changed

- links to change resolution of histogram now properly URLEncode parameters (like the query)
Fixes for issue #777

- Resolution of histogram now depends on time range of search, making it more reasonable
Merge branch 'issue777'
Merge branch 'issue862'

Conflicts:
	app/controllers/SearchController.java
Updat rest client to 5cd58c0b76bff50b27befcd92ecc4027bca2718e
Refactoring: merged common code in search controllers
Try to speed up build by optimizing travis/graylog2-server.sh
Upgrade to sbt 0.13.5
Consolidate sbt build

We got rid of the 'package-snapshot' command and can now use 'universal:package-zip-tarball'
directly. The name of the artifact is overridden in case of a SNAPSHOT build and the example
config will be mapped into the archive.

Selfie of the author of this changeset during basically every stage of development and
contact with SBT:

http://31.media.tumblr.com/bcaca0957cae39e4fd6fa056167f3603/tumblr_n8eup6Xzjv1s373hwo1_400.gif
Merge pull request #888 from Graylog2/fix-snapshot-directory-in-tgz

Fix directory in snapshot archives
Speed up Travis CI build by removing unused services
Possible fix for issue #890

- added additional check to ensure sampling of data only applies to search result chart widgets
Adding correct source field for radios when showing messages from input.

Fixes #856
Bumping version to 0.21.0-beta3.
Bumping version to 0.21.0-beta4-SNAPSHOT
Only append width query parameter if it has a value, refs Graylog2/graylog2-server#696