Add cpsection for webservices

This is the 3rd series of patches in support of adding webservices to Sugar. (See [1])

0001 adds ~/.sugar/extensions to sys.path. This is necessary for installing webservices in the user directory as well as /usr/share/sugar/extensions

0002 adds a new control panel section to support accessing to webservices.

[1] http://wiki.sugarlabs.org/go/Features/Web_services