channel settings ui refactoring, styling & bugfixing/improvements

[waxenegger]

see: ome/design#75

• https://trello.com/c/02NvAiA8/27-settings-tab
• https://trello.com/c/brhz6sX0/26-size-of-tab
• scalebar always on top of other ol3 controls
• channel buttons converted to button group incl. drop-down for colors
• cherry-picked all commits from Started on css styling of tabs & ROI panel #59
• only center if roi that has been clicked on in table is out of view
• mac shortcuts
• int -> rgba padding fix
• drawing mode abort on table interaction

[snoopycrimecop]

Conflicting PR. Removed from build iviewer-merge#263. See the console output for more details.
Possible conflicts:

• PR OL3 style changes for controls (esp. zoom) #56 waxenegger 'OL3 style changes for controls (esp. zoom)'
  • src/css/app.css
• PR Rois tab ui reshuffle and styling #57 waxenegger 'Rois tab ui reshuffle and styling'
  • src/css/app.css

[will-moore]

Pushed some more commits to #59 for cherry-picking.

[jburel]

Selection in table/switch mode works. This is better I think

[jburel]

Could you add copyright in the various javascript files modified in this PR?

[will-moore]

All seems to be looking good and working fine for me.

[jburel]

Merging
We can add copyright in js file in a follow up PR.