[add] select pads per group
[fix] data code and message for empty database result set

-set 'success' values, e.g. code: 0, message: 'ok', for database
queries returning no records, e.g. delete queries
[add] add/remove authors, and list authors of a group's pads
[add] get global author list

-move original 'epc_authors' routine to 'epc_authorsOfPads'
-add new epxCalls to 'listAllAuthors' and 'getAuthorMappers'
[imp] error handling for ajax calls

-standardise ajax wrapper usage to expect js 'undefined' for failure
-cope with ajax call to unsupported methods
[imp] remove superfluous form element wrapper
[imp] remove fixed settings / info width restraint

-remove status container's 100% width + fixed margins setup and
rely on div's 'display: block' default 100% expansion in natural
rendering flow
-adding padding to adjacent containers to cover the bleeding
from 'status' caused by the necessity to specify '100%' height to
enable vertical overflow
-wrap lower 'select' containers in an absolutely positioned div to
account for the above padding hack
[fix] footer background image for opera browser
[add] display basic pad info on selection

-implement js 'epc_padsInfo' function
-implement php 'epxCall' function's 'getPadCreated' query
[add] session select controls and js method stubs

-move groups adjacent to pads as they are more 'connected' than
groups/authors