P001Model: Swizzle stuff renaming

• `dealloc_withModelWillDie_IMP` renamed `dealloc_withModelWillDie`.
	» The `_IMP` is unnecessary details; this is the actual function that is called and used at runtime, not something that's a representation or copy of the actual compiled and run code.  So, not need for differentiate when it's just a method skipping the compiler's ownership rules in favor of file scoping and having the first to args listed explicitly.
	• Also, declaring `dealloc_withModelWillDie()` within P001Model's internal @interface.
• `+ swizzleDeallocForModelWillDie` and `unswizzleDeallocForModelWillDie` methods renamed to `P001Model_swizzleDealloc` and `P001Model_unswizzleDealloc` respectively.
	» Prefixing things seems appropriate considering the point of the dealloc swizzle is for P001Model's ends.  And the “ModelWillDie” is somewhat irrelevant; P001Model could throw other stuff in it's dealloc_withModelWillDie wrapper method.
	• Renamed calls in P001ModelTests' testModelSwizzleUnswizzle and testModelWithoutDeallocSwizzleUnswizzle.
• `subclass` in `+ P001Model_swizzleDealloc` and `+ P001Model_unswizzleDealloc` renamed to `swizzleClass` in the former and `unswizzleClass` in the latter.
• `kModelWillDieSwizzleAssociationKey` renamed to `kIsDeallocSwizzledAssociationKey`.

Minor:
• `thisClass` local var in init.