Plugin Installer Speedup

Speed up plugin installation.

• Don't load featured plugins.
• Make Search Plugins button visible.
• Set focus to search field.
• Skip plugin install confirmation.
• Add admin menu items under "Plugins" for Upload Plugin and Favorites.
• Add admin bar menu item under "+ New".
• Remove "-master" from (mainly GitHub) ZIP archive names.

No admin page for this plugin. Ready to go right after activation.

GitHub repository

The feature of plugin upload from URL has been moved to a MU plugin.