Misc. add to region enhancements

[m-nadji-tehrani]

When adding a cortical area to a region:

• rename the window title to "Select a Target Brain Region"

• in the case there is no subregion available, directly launch create new region window

• rename "add region" button to "Create Brain Region"

  

• When displaying the candidates to user for adding to a region, do not show the ones already added

• Enable user to select multiple areas at the same time when adding. (need to address multi select holistically)

• rename "Select object from genome" to "Select Candidates"

  

[Amir-Rasteg]

Current redesign handles added these improvements