[#1409] Fix the e-mail bodies' translation strings

We ended up creating a string with extra whitespace before the paragraphs,
like "...to be reset\n\n Please click the following...".

But the i18n message key doesn't have these whitespaces, so we always send
that in English. To solve it, we could either fix the message key in all .po
files, or change how we construct the string in mailer.py. I prefer the
latter.
[#1409] Remove pdb breakpoint
Remove mentions to "Comprehensive Knowledge Archive Network"

CKAN stands for CKAN.
[#1409] Change string formatting to use "{foo}".format(foo="bar")
[#1429] Pass came_from to login handler after creating a user

Otherwise you lose the language setting for the UI. I'm not entirely
sure but that may involve two redirects.
[#1429] PEP8 fixes
[#1433] Flesh out the context for group/about setup_template_variables.
[#1449] Fix extras deletion

The custom-fields module was actually disabling the fields when clicking
the delete extra cross button. This prevented the key and value from
being sent, which caused a validation error.
We now change only the class to make it look disabled, which should be
good enough.
[#1449] Remove unneeded tests
Merge branch 'master' into 1449-cant-delete-extra
[#1461] remove repeated sort code in package_search
[#1460]  Change button to input so that ie7 works.  Also needed to change way params are got as value needs to be the thing shown on the input
Merge branch '1460-fix-group-remove-ie7'
Merge branch '1461-repeated-code-in-package_search'
Merge pull request #1429 from okfn/1429-language-reset-after-register

UI language reset after account creation
Merge pull request #1449 from okfn/1449-cant-delete-extra

Can't delete extra
Merge remote-tracking branch 'origin/1433-fix-context'
Big docs reorganization

This is not as big a change as it looks like, because it's taking the way the
docs were already organized by audience and making it explicit by creating
top-level dirs for each audience and moving all the docs into them.
Also cleans up a couple of loose ends where particular files didn't fit into
the organization-based scheme, fit them in. It then has to touch a lot of files
in doc/ to update Sphinx cross-references.

Create 8 top-level directories, one for each different audience:
User guide, sysadmin guide, maintainer's guide, API guide, extending guide,
theming guide, contributing guide and changelog.
(User guide, sysadmin guide and changelog are actually just files, not
directories, because they only need one file each.)

- New overview on docs front page explains the high-level structure

- Added a section to the documentation guidelines explaining the new structure

- Lots of feature pages moved into new maintaining/ dir

- Configuration.rst moved into maintaining/

- getting-started.rst moved into maintaining/

- Move Solr multicore appendix page into maintaining/,
  remove the appendix section itself as no longer needed

- Remove the "Features" index page, no longer needed as the pages just go into
  the "Maintainer's guide" now

- Create doc/maintaining/installing/ subdir and move the installing and
  deployment docs into it

- Create doc/maintaining/upgrading/ subdir and move the upgrading docs into
  it

- Move api.rst and legacy-api.rst into new api/ dir

- Move test.rst into contributing/

- Fix Sphinx references all over the place to point to the new file locations
Fix a Sphinx error (broken links)

@kindly
Merge branch 'master' of github.com:okfn/ckan into docs-reorg