Added settings page with new features (v1.0.7)

* Added a new settings page.
* Added contact form to get in touch with me (the author).
* Added ability to toggle abtract tooltips on/off.
* Added ability to set length of abstract in tooltip.
* Added ability to append "Open with Read" link to bibliographic entries.
* Add target="_blank" (open in new window) to links in bibliography. This can be toggled in new settings page.
* Added a nag notice to remind you guys to rate the plugin.