refactor type
Move submenu logic of instance settings in separate module lib.settings
Split user settings in multiple pages (fixes #174)

This splits the user settings page in multiple pages:

* personal settings
* login settings
* notification settings
* advanced settings

This is done the same way as the instance settings are already done.

Most of the forms are refactored towards form element creation using
`templates.form`, some aren't yet as they're more complicated. Some
styling introduced in #456 has been removed again, as it looked bad
within the new layout and should be resolved generically instead.

The gender field adopted minor changes from the ongoing discussion in
#468, as this is in every case better than what was there before.

The user actions have been moved to the *advanced* submenu, but are
still displayed on top, as stupid as before.
Adapt mass message unsubscribe link to new user settings url scheme
Merge pull request #476 from nidico/feature-174-user-settings-layout

Feature 174: Refactor user settings layout
Allow to increase maximal instance key size from 20 to 63 characters

This lifts the 20 characters maximum instance key restriction on
database level to 63 characters; this is the maximum length of a label
of a node of a FQDN (meaning any part between dots in the domain name),
according to RFC 1034 [0].

The default setting of the configuration option
adhocracy.instance_key_length_max is still 20 characters, but can now be
increased up to 63.

Some examples:

* The longest currently used instance key has 35 characters:
stadtbremisches-ueberseehafengebiet (geo branch has allowed this for a
while).

* The longest German municipality title "Vereinbarte
Verwaltungsgemeinschaft der Stadt Geislingen an der Steige" wouldn't be
covered by the 63 characters limit, as it has a length of 70 characters.

[0] http://tools.ietf.org/html/rfc1034#section-3.1
Also increase maximum key length in instance key regex

Fixup for 59accdc4252afe00d307a1dc6e3811ce957f910c.
Permanently save "disable all tutorials" setting (fixes #109)

This now uses the `no_help` user attribute for this purpose.

Note that disabling of single tutorials is still only stored in a
session cookie.
Merge pull request #477 from nidico/feature-109-remember-disable-all-tutorials-setting

Permanently save "disable all tutorials" setting (fixes #109)
Merge pull request #483 from xi/feature-refactor-type

refactor type
pep8, pyflakes
Add clearfix in sorting slidedown

This makes all sorting groups appear horizontally aligned.
Add userbadge support based proposal sorting (votedetail)

This adds proposal support by each votedetail enabled userbadge to Solr
and allows to sort by support of these user groups.

Note that this only adds score (pro minus con) and not most votes, most
ayes, most nays, controversy for the user badges, as this wouldn't
easily fit within the current UI.
Allow to export proposal and comment ratings
remove some css that was left from before we used gradients for buttons
fix thumbnail margin
fix register button arrow placement
fix morelink arrow placement
fix wrong color in dropdown menu when parent is selected
Unquote came_from before redirect

As we urlencode the came_from URL in lib.helpers.camefrom_querystring
and other locations, we need to unquote it before performing redirects.

This most likely fixes hhucn/adhocracy.hhu_theme#411.