Bump version v0.7.2.

 * Improve tests.
 * Optimize CSS.
 * Make menu collapsable on mobile devies.
 * Get rid of using external fonts from CSS.
 * Fix handling of empty controller_id.
 * Fix a lot of typos.
 * Improve finish page of wizard.
 * Add "external" icon to LuCI link.
 * Improve working with datatime.