P001Model: is/set/resetDeallocSwizzled helpers

Added `P001Model_isDeallocSwizzled()` check method and `P001Model_set/resetDeallocSwizzled()` modification methods to wrap up the objc_get/setAssociatedObject stuff.

Now using `P001Model_isDeallocSwizzled` in init, P001Model_swizzleDealloc, and P001Model_unswizzleDealloc; `P001Model_setDeallocSwizzled` in P001Model_swizzleDealloc; and `P001Model_resetDeallocSwizzled` in P001Model_unswizzleDealloc.