Remove Legend link on the Info popup.

Fixes #353.
Remove person from WMS-derived Data Custodian information.

Fixes #352.
Don't show legends for data sources that are not shown.

Fixes #351.
Highlight panel buttons when the panel is visible.

Fixes #349.
Add opacity slider to legend.

And remove it from the Info popup.

Fixes #350.
Merge pull request #355 from NICTA/minorB3Issues

Fixes several minor b3 issues discussed today