Fixes the broken support for overriding settings with ENV variables.
closes #5769

closes #5739

closes #5806

fix(templating): another fix for repeating panels and having old panels/scoped vars stuck after switching repeat variable, fixes #5795

fix(graphite): minor fix/improvement to graphite error handling when doing metric exploration in query editor, fixes #5778

* One of the homebrew folks first asked for a wrapper script to make launching grafana easier. Later I was asked to remove it and submit it upstream, so here it is.

* add instructions for installing grafana HEAD from git with homebrew back to the docs

feat(templating): fixed issue with template variables set to reload on dashboard load being issued multiple times, fixes #5637