[Twisted-Python] Declaring some new supported builders (platforms)

[exarkun at twistedmatrix.com]

Hey guys,

Please comment on <https://github.com/twisted-infra/twisted-buildbot- 
configuration/pull/4>.  It changes the following builders/configurations 
from unsupported to supported:

    debian6-x86_64-py2.6
    debian6-x86_64-py2.6-glib
    ubuntu-12.04-x86_64-py2.7
    ubuntu-12.04-x86_64-py2.7-glib
    fedora19-x86_64-py2.7

Jean-Paul