Elastic UI Chrome Accessibility

[aphelionz]

Subset of tickets in #614 that deal with the meta-interface of Elastic UI, anything that exists outside of the elements themselves at https://elastic.github.io/eui/

• Home link in upper left lacking context, title attribute Home link in upper left lacking context, title attribute #616
• Color Theme Picker Lacking Context Color Theme Picker Lacking Context #617
• Color Theme Picker Dropdown Instructions Color Theme Picker Dropdown Instructions #618
• Color Theme Picker Keyboard Trap Color Theme Picker Keyboard Trap #619
• Return key does nothing in the search box Return key does nothing in the search box #620
• Filtered Menu Lacks Context Filtered Menu Lacks Context #621
• Version Link should read "version" before version number Version Link should read "version" before version number #623
• Main Heading should be focused after a manu item is selected Main Heading should be focused after a menu item is selected #622
• Sketch Libraries Link should read tooltip on focus Sketch Libraries Link should read tooltip on focus #624