Compatibility fixes

* Queries in URLs are no longer ignored
* Atom XHTML content is now supported
* For Atom feeds, source_link now falls back to the requested URL

In addition, the argument ordering in re.sub call
has been corrected and summary is no longer empty.

Big probs to Huy (xrvs.net) for testing.
-----BEGIN PGP SIGNATURE-----

iQGzBAABCAAdFiEE6Q4RuASTNDthMuOUJxSLLAaiIksFAmNrcCoACgkQJxSLLAai
Ikt3lgv/dsgjD4FJaFspC6UDHjJ/vupCYSPHs+JKG4pU1KP+Hz6Za1Nxi8DcRdfq
nptzEUmE0F+ZbOL+ZXdJvZOKU+Tf7dyMMX/1GoSK58APLzXD4u1L7mbngZZiXvBa
CkEfCvp0Z4aT6V+S+Oc9Z+ETHhec2xr8/WvLdqEJAvdvCjidc9bERNbd9G1+iSN9
WKANVagtNKxtkuUfvX0BC4nm/63vmAGgUBDjfLb2FYvVUfN/8ZIyx3xT59dra7UR
3f+WdGMPhbf2iwPTy0IPeP4hu/z+KuW/Gxz0N1lVLo1DN1R46C4rE4mLLU3op4IJ
cC59ZFixvxgIsvbMdaBFiDaHkhNcDkO2FML6siEyhUTffQJ+Q+RKlwpRS84Ctkbx
I8Kwdr+kDkapxgAFKd+hmXfGQWtfF/07QmpoFV24BLkPypaDC5OaxY7sxErB8keM
idqD9cD1cefvHZLGuFuJAJiBTpOrjOpv+7ZkOm/Ee2/6dWMgPgPjl01rVnCJZnS+
XeE5phYT
=WuGK
-----END PGP SIGNATURE-----