This decision was made to reduce the complexity of using .include whilst
juggling with tools/scaninc and tools/preproc:
- tools/scaninc doesn't apply the proper search rules for .include (it
  assumes #include behavior). In particular, it doesn't consider paths
  starting from $PWD, and doesn't scan the included files as a result.
- .include had to be processed before #include by preproc in many cases,
  as code was being included that had to be preprocessed by CPP (think
  of #define). This contradicts standard GCC behavior.

To make include paths consistent across the asm/ data/ and src/
directories, the following files were moved:
- constants/ → include/asm/constants/
- asm/macros/ → include/asm/macros/
- asm/macros.inc → include/asm/macros.inc
- include/macros/m4a.inc → include/asm/macros/m4a.inc

As part of the necessary changes for this to work, the scaninc method in
the makefile was improved to generate .d files that don't choke when
files are missing.

* decompile sub_8091290

* decompile sub_80912c8

* rename functions / struct field

* more names

* decompile 80913A0

* decompile GetItemMove

* decompile sub_80913E0

* rename function

* decompile CanSellItem function

* rename inventory struct

* add some item check functions

* fix renaming stuff

* this file shouldnt have been here

* forgot merge conflict

* decompile more item functions

* rename some stuff

* fix HM/TM naming

* Update src/code_801AFA4.c

Use enum value for USED_TM

* Fix incorrect value

Co-authored-by: Seth Barberee <seth.barberee@gmail.com>

* splitting lots of pokemon square and labeling lots of other things

* actually commit this stuff

* more moving data and things

* more screen work

* split out some pokemon dungeon data

* lots of data work

* push more data work

* split kecleon, decomp another kanghaskhan func, and try to doc UpdateBGControl more

* lots of item work

* label more item things

* subtype -> category and doc types/category