stackbuilder - wizard: Allow app categories to be hierarchical.

Log Message:
-----------
Allow app categories to be hierarchical. We simply use a separator ('\') in the category string to do this, to ensure backwards compatibility with older versions of StackBuilder.
[Sachin Srivastava]

Modified Files:
--------------
wizard:
AppList.cpp (r1.20 -> r1.21)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/stackbuilder/wizard/AppList.cpp.diff?r1=1.20&r2=1.21)
wizard/include:
AppList.h (r1.10 -> r1.11)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/stackbuilder/wizard/include/AppList.h.diff?r1=1.10&r2=1.11)