Some XML reading changes

* Got rid of the XmlReader::attribute and XmlReader::intAttribute
  accessors which were potentially a little inefficient.

* Used readNextStartElement and skipCurrentElement in more places to
  simplify the XML parsing code.

* Introduced a bunch of setters rather than declaring friends. I guess
  I'm just not really fond of "friends" since it makes code harder to
  move around.

Reviewed-by: Erik Schilling
Fixed potential memory issues in SpriteItem

* mSprite started as an uninitialized pointer
* It was always being dereferenced in the destructor
* There was no proper cleanup when the sprite ref was changed

Reviewed-by: Erik Schilling
Changed import of Qt to QtQuick in qml files
Tweaked ServerPage a little
Simplified ItemDB::getInfo
Dropped debug output for xml parsing

This was spamming only.
Fixed caching of spritedefinitions
Added display of characters to the CharacterPage
Temponary fixed negative hair ids

to be replaced with a proper solution later (will make content incompatible)
Allow setting serverlist via commandline argument
Allow multiple sprites for equipment per item
Added first npc support

Only supports plain messages and next / end command
Automatic update of qmlapplicationviewer by Qt Creator 2.7.0
Fixed compile against Qt 5

Still works with Qt 4, for now.
Implemented move by keyboard
Added support for npc choices
Updated libtiled classes to the latest from Tiled

With theoretically a small increase in rendering performance.
Simplified Being::lookAt

When walking exactly at a 45-degree angle, it prefers the up and down
directions. This is the same behavior it had before.
Fixed updating of being positions

It was not updating any beings that came after the player.
Fixed handling of map changes

* No more duplicated entities
* No smooth camera movement on map switch
* Improved fade-in on new map using black overlay rather than using the
  transparency of the map itself

Had to drop the Behavior with the SpringAnimation since I couldn't find
a working way to disable it temporarily for the map switch. We'll see
whether the new timer approach works fine.