Corrected quoting in warning message

qDebug already adds quotes and spaces, so they were doubled.
Added support for external tilesets
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