Potion effects should be hidden until discovered
Factored a NIFStream class out of the NIFFile class.

Split NIFFile into two parts, NIFFile which is cached and is a container
for a parsed NIF, and NIFStream which is a class specialized for parsing
NIFs. This required a semi-sweeping change to make all record classes
accept a NIFStream instead of a NIFFile as an agurment to their read
functions.
refactored NIFFile parse to get better code/data seperation
renamed low-level NIF related files and include guards to conform to naming convention
renamed high level NIF files...
Magic effect icons for spells
Magic effect icons for permanent enchantments
Implemented potion & ingredient effect stacking
Fix ingredient effect display
Fix headers including whole MyGUI.h, forward declare where appropriate, and fix some deprecated types (WidgetPtr)
Merge branch 'master' of git://github.com/zinnschlag/openmw into graphics
Merge remote-tracking branch 'scrawl/effects'
Merge remote-tracking branch 'scrawl/includes'
Merge branch 'master' of git://github.com/zinnschlag/openmw into graphics