Help text for non-empty text options.
Remove "Restore to defaults" button.

And line up main frame with the first two columns of the main options
table.
Move "Custom key mappings" above the fold.
Activate "Save" button on input.
Activate "Save" button on input (non-empty text areas).
Tweaks to options page.
Move custom search engines above the fold.
Reduce the size of the excluded URLs container.
Delete rule button for exclusion rules not tab selectable.
Reposition save button such that "always" on screen.
Control-ENTER in text option blurs and saves all options.
Options help text and grammar.
Do not line wrap some text options.
Tone down help messages in footer.
Make help text on options page more concise.
Consistent capitalization on the options page.
Merge 'explain-default-options-remove-restore-button'.

Conflicts:
	pages/options.html