Merge branch 'issue-2971' of https://github.com/alexanderzobnin/grafana into alexanderzobnin-issue-2971

fix(dashboard): fixed issue triggering refresh after leaving fullscreen/edit mode with time range change

fix typos in GitHub Issue Template

Add Prometheus annotations doc

This reverts commit 8efa94e4.

Revert "issue #4747 - add date and time units to singlestat panel."

issue #4747 - add date and time units to singlestat panel.

Pseudo-elements must start with double colons pseudo-element

fix(graph): remove panel width cache, causing issues, does not handle window resize and fullscreen to dashboard, #5297

* OpenTSDB: consistent options for http requests

 . the get function wasn't using the same request options wrt to credentials/auth as
   the timeseries http request

* OpenTSDB: `_get` `_performTimeSeriesQuery` refactor copied code

fix(share): fixed PNG render link generated from share modal when opened from edit mode, fixes #5295

* Add default-url property for datasource-http-settings directive.
This will allow to set default url for datasource.

* Fixed spelling.

* Use typeahead for url suggestion.

This reverts commit 3d776851.

Prepended first line to export file containing
`sep=;\n`
which I believe should be all that is required for Excel to interpret the CSV file as semicolon delimited.