TYPO3 Core

The update wizard is still pretty hard to understand, both as a coder, and as
a user.

Last week Masi made a change which depends on the update wizard, but nobody of
us knew where and how to put that change on the list.

Solution:
I made various changes to the update wizard:

- Separate entries in cms/ext_localconf.php to make things easier to
understand

- Change label of the "next" button depending if we're going to up- or
downgrade. Easier to understand once again.

- Replaced some < b > with <strong> tags, changed some more formatting

- Change getUserInput() method, there's now just a selector where users can
downgrade the behaviour of this system.

- Removed all str_replace(chr(10), '< br / >', $input) occurences. From now on,
the definition in ext_localconf.php must contain all formatting.

- Add a new method showChangesNeeded_short() which prints the titles (newly
introduced) of all missing features.

- Renamed the two array keys which are used as labels (afaik keys may contain
whitespaces, and since the key is not used for anything but the label, this
should be fine)

- !!! Never cache any extension scripts (ext_tables.php and ext_localconf.php)
while using the Install Tool. Doesn't seem to cause any problems, but
seems to avoid various problems while testing this... Might likely solve
some other problems (e.g. when having broken temp_CACHED_* files)...

- Finally, add Masis allow-address-tags condition to the list of features.

How to test:
Unset the compat_version in localconf.php and enter the update wizard in the
Install Tool.

- Try updating for the first time (changes directly to 4.2 because this is the
current branch)
- Try switching back to version 4.0
- And now, go back to the latest version (4.2) again. This time, only one
change (the address feature) should be displayed.

Comments:
I would like to get some feedback about this from a typical user who has to
use this feature. So if you are reading this, please test the patch and reply
to me directly.
(issue imported from #M6507)