develop/libraries/box_lib: Post-SVN tidy

- Move source code from `trunk` into program root directory.
- Update build files and ASM include paths.
- Note: Line endings standardised from `CRLF` > `LF`, so best to view diffs with whitespace changes hidden.

programs/develop/str_double/str_double.asm

@@ -24,7 +24,7 @@ include '../../proc32.inc'
 include '../../macros.inc'
 include '../../KOSfuncs.inc'
 include '../../load_lib.mac'
-include '../../develop/libraries/box_lib/trunk/box_lib.mac'
+include '../../develop/libraries/box_lib/box_lib.mac'
 include '../../develop/info3ds/info_fun_float.inc'
 include 'lang.inc' ; Language support for locales: ru_RU (CP866), en_US.