Moved everything to do with managing options to a separate file and implemented filters and hooks to leverage the Options API to the max.

Also:
- better application of the settings_prefix property
- improved charset support for forms
- improved availability of debug info on settings page
- allow other plugins to add to our settings page
- stabilized inclusion of options-head.php for settings updated/error messages
Merge branch 'master' of github.com:jrfnl/wp-plugin-best-practices-demo

Conflicts:
	class-demo-quotes-plugin-settings-page.php
	class-demo-quotes-plugin-widget.php
	demo-quotes-plugin.php