Added support for global datasource, view-only mode, etc.

Added support for a view-only mode, for use in scripted dashboards

updated changelog

Closes grafana#209, sub folder with project name and version suffix i…

…n release zip files

Merge pull request grafana#185 from nikicat/master

added graphite functions: percentileOfSeries, sumSeriesWithWildcards, averageSeriesWithWildcards

updated readme and version bump

version bump to 1.4.0 and link to annotations wiki article

Closes grafana#86, dashboard tags and tag search feature is now done!…

… turned out pretty good!

build/grunt script fixes

Implementation of legend values (min, max, current, total, avg), Closes 

grafana#60, Fixes grafana#14