Merge pull request #163 from sandriu/master

Refs #2283: min-width:10px added to submenu items
Mobile menu positioned from top of the page
Merge pull request #164 from dragos-dumi/master

Mobile menu positioned from top of the page
Fix for mobile menu
Merge pull request #165 from dragos-dumi/master

Fix for mobile menu
Refs #2283: show hamburger menu on 800px and beyond
Refs #2283: move hamburger menu to left
Refs #2283: custom colours for hamburger menu
Refs #2283: custom colours for accordion global menu for ASCOBANS
Refs #2283: custom colours for accordion global menu, for all themes
Refs #2275: arrange search box on 800, 600, 480px mobile resolutions