added accepted file type to assets manager uploader
CDB-245 #resolve - fixed problem when drop an unsupported file type
common submodule updated
dropbox  pane updated triggering new type
import dialogs checking services url extensions like Dropbox
added new message error - connection - in file import pane
CDB-259 #resolve - fixed problem in add layer dialog when user can't create new tables
asset manager broken spec fixed :)
CDB-260 #resolve - Enable funcionality of checking quota tables when a new table is requested
CDB-264 #resolve - text for add layer dialog tooltip changed
connectivity error caught
Merge branch 'CDB-226' into release/staging