* Wrapping all headers that are in agi_pre.h with AGI_PRE.
* Sorting alphabetically.
* Same operation as r3515.
Note: This is broken when precompiled headers are not in use, I'll fix that after this commit so the two changes don't get jumbled up.
Originally committed to SVN as r3525.
* Update agi_pre.h to include some missing headers, also move required windowsheaders to the top of the list
* Use <> versus "" for the wx header in avisynth_wrap.cpp
* Remove xx/wx.h from agi_pre.h as it's included by wxprec.h.
Originally committed to SVN as r3513.
