TYPO3 Core

http://review.typo3.org/38004 removed the typo3/mod directory
with the main modules and their configuration and added the configuration
to `$GLOBALS['TBE_MODULES']`directly.
However for that a sub array key `configuration` was used,
which is inconsistent with all our current API and its usages
across other modules, leading to the situation that
this configuration was basically ignored.

On top of that, http://review.typo3.org/39316 introduced the possibility
to use sprite icons as module icons, which used the configuration
key `icon` in the above mentioned sub array key `configuration`,
making this key the only option evaluated in the sub array.

This change removes this sub array and moves the sprite icon configuration
on top for consistency. For that the key must be changed
to 'sprite-icon' as 'icon' was already taken for
Extbase module icon configuration.