Fix some issues that cause PHP notices
If a preset was not saved after new rules were added there will be no
color value for the rule/preset combination which can result in a notice.
Removed unneeded `$selector` parameter from flexicolor_delete_selector
Adjust fieldset on configure form
Also show when custom colors are used in the options of the switch form
block. More work should be done to show the state of custom colors versus
a selected preset on the configure form.
Add correct redirects when submitting or canceling forms
Drupal 7 uses `$form_state['redirect']` in the submit function, compared
to `$form['#redirect']` in the form function in Drupal 6.