Fixed issue with using template variables in panel titles, and text panel, when selecting All option in variable

Dashboard: time range can now be read from URL parameters, will override dashboard saved time range, Closes #787, Closes #761

The elasticsearch datasource will now better handle language specifics when making the search partial (ie for search as you type).  This means the search field will now support significantly more complex searches such as:

    title:foo AND title:bar OR baz
    title:mysql AND [3306 TO 3308]
    web~
    title:foo AND -bar

Adding in global search id counter so that async search responses can be discarded if a newer search is being processed.  This prevents older search results from clobbering a newer search that happened to complete faster.

Fixed issue with editing text panel, removed a function from dashboard controller that I though was not used, turned out it was