Fixes #1483

See #1551

Changed the values recognized by the general config parser.
If value in config is a boolean it is recognized as boolean, not if it
is a string.

Fixes #718

The opera work around is still needed though! O_o

Standardized node.textContent is available since IE9

This adds the possibility to define file with protected users in the
config cascade to be used with the plain auth mechanism.

This makes it possible for farms to have way to inherit Farmer users in
animals.

Our minimum PHP version requirement is now over 5.3, so this workaround is
not needed anymore. See also c9454ee3

reusing the diff colors as suggested by @selfthinker

restoring of mediafiles failed

missed a line in my last commit

This makes it easier to create tabs with an active tab (no need for
additional markup)

A few fixes.

we already do it for other passwords, so it makes sense to do it here as
well.

New Python Django application default to PBKDF2 with SHA256 as a
password mechanism. This adds support for that mechanism in our
password hasher class. This will be needed in the tests for the new
PDO auth plugin.

This makes sure the provided callback is using alphanumerics only. I'm
not sure this is needed, but better safe than sorry.