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/system/MyKey/trunk/MyKey.asm

@@ -1,3 +1,6 @@
+; SPDX-License-Identifier: NOASSERTION
+;
+
 ;
 ;   MyKey. Version 0.2.
 ;
@@ -26,7 +29,7 @@ include 'string.inc'
 include '../../../macros.inc'
 include 'ASPAPI.INC'
 ;include 'editbox_ex.mac'
-include '../../../develop/libraries/box_lib/trunk/box_lib.mac'
+include '../../../develop/libraries/box_lib/box_lib.mac'
 ;include 'load_lib.mac'
 include '../../../develop/libraries/box_lib/load_lib.mac'
 include '../../../dll.inc'