More networks added, EL "post" added, templates fixed:

More networks added, EL "post" added, templates fixed:
- New advertising network 'City-Ads' and 'Gold-Sponsor' added
- Templates fixed, bad handling of network_type_id
- New EL code {%post=foo%} introduced, it is similar to the GET code, so you
  can access elements in $_POST. Also this code has no support for extra
  functions
- TODOs.txt updated