Fix typo in ProxyHead().

It looks like there is just a typo in a variable name in the ProxyHead() function.

PhpStorm has some excellent features that other IDEs do not have that allows errors like these to be found. Other IDEs do not have said features and thus do not find said errors.
Merge pull request #2350 from vanilla/hotfix/proxyhead-port-fix

Fix typo in ProxyHead().
Allow device types to overridden in the config.

This feature currently only works well with our infrastructure’s varnish device detection.

Currently, tablets will display the desktop theme and apps will display the mobile theme. This feature allows you to specify a config setting to change that. So for example specifying `Garden.Devices.Tablet = ‘mobile’` will make tablets look like mobile devices on the server.
Merge pull request #2351 from vanilla/hotfix/device-override

Allow device types to overridden in the config.
Fix content-type header
Merge pull request #2352 from vanilla/hotfix/header-charset

Fix content-type header
Relax the permission requirements for viewing the dashboard.

Since most dashboard links use the Garden.Settings.View permission check then that permission should also be allowed to view the basic dashboard index.
Merge pull request #2354 from vanilla/hotfix/view-setting-index

Relax the permission requirements for viewing the dashboard.
Merge branch 'master' of github.com:vanilla/vanilla into feature/multisite

Conflicts:
	plugins/VanillaStats/class.vanillastats.plugin.php