* Created awesome filter classes :)
* Made all filter effects use the filter classes instead of having the same implementation everywhere.
* Added a Python API for LTI IIR filters.
* Fixed a warning in creator.c that was introduced when adding game autoplay.
Some points of the refactor not sorted by importance:
* Fixed immutability of readers and factories (there are exceptions...)
* Fixed copy constructors and = operators
* Removed messaging system
* Removed reader types
* Added const where possible
* Using initalisers when possible
* Avoided use of pointers when possible
* Removed AUD_NEW and AUD_DELETE macros
* Removed useless NULL pointer checks
* Fixed exception catching
* Fixed some yet unknown bugs
* Lots of other stuff
