Merge branch 'r/1.0' into develop
Spacing in readme.
Add screenshots
Update screenshot-3
Simplify plugin loader
Add meaningful error messages. Resolves #3.
Add usage and shortcodes to settings page.
Remove IS_PLUGIN_SLUG and IS_PLUGIN_DIR constants. Fixes localization issues.
Add email provider presets. Add nice error messages for popular email services. Validate data entry. Allow port and TLS to be overridden. Resolves #6.
Typcast port and tls. Remove console.log()
Add support for Gmail search queries.

* Revise all count queries to go through count method, reducing the number of places the cached option must be defined.
* Automate shortcode and do_action code samples on admin page.
Add support for Gmail priority inbox and categorized inbox. Resolves #7.
Merge branch 'f/gmail' into develop
Add all shortcodes to nav-menu metabox.
Version bump
Merge branch 'r/1.1'