Fix broken links in the 2.2 docs

I used ``make linkcheck`` to find other broken links in the current docs and tried to fix them as good as possible.

- For some, there was just an URL or domain change, those are easy.
- For others, there is the same content in another context, I tried fixing those, too.
- For the last ones, there simply is no replacement, they should probably deleted.

Now I tried splitting it up into different commits for the different "issues" so you could easily only just take some of them, if you disagree with some of my fixes. ;)

Futhermore, there are some additional broken links that I don't know how to fix, one of the devs should probably look through them:
```bash
egrep -v 'redirected|local|127\.0\.0\.1|deprecated|path/to/private/index|no host given' _build/linkcheck/output.txt
building_docs.rst:130: [broken] http://bitbucket.org/pedersen/tg_2_1_docs: HTTP Error 404: NOT FOUND
building_docs.rst:161: [broken] http://bitbucket.org/pedersen/tg_2_1_docs: HTTP Error 404: NOT FOUND
main/Contributing.rst:4: [broken] http://docs.turbogears.org/TurboGearsTeam: HTTP Error 404: Not Found
main/Contributing.rst:57: [broken] http://docs.turbogears.org/patching_guidelines: HTTP Error 404: Not Found
main/Contributing.rst:88: [broken] http://docs.turbogears.org/patching_guidelines: HTTP Error 404: Not Found
main/Deployment/FastCGI.rst:32: [broken] http://trac.saddi.com/flup: <urlopen error timed out>
main/Deployment/FastCGI.rst:17: [broken] http://trac.saddi.com/flup: <urlopen error timed out>
main/Extensions/Geo/TileCacheTutorial.rst:57: [broken] http://svn.tilecache.org/trunk/tilecache/tilecache.cfg: <urlopen error [Errno -2] Name or service not known>
main/Extensions/Geo/TileCacheTutorial.rst:57: [broken] http://tilecache.org/readme.html: HTTP Error 404: Not Found
ain/Templates/Genshi.rst:13: [broken] http://www.kid-templating.org/: <urlopen error timed out>
main/Templates/Genshi.rst:7: [broken] http://www.kid-templating.org/: <urlopen error timed out>
modules/thirdparty/webhelpers_paginate.rst:166: [broken] http://workaround.org/cgi-bin/hg-paginate: HTTP Error 404: Not Found
```