modified grunt css task to copy only the changed file CDB-2807
CDB-2807 #resolve - grunt development processes improved
CDB-2810 #resolve - added nasa basemaps
CDB-2810 - added error + fixed date problem
changed attribution + added date in NASA name + other fixed
hiding date combo when night type is selected in NASA tab
fixed and added tests for basemap chooser
Merge pull request #401 from CartoDB/CDB-2810

CDB-2810