* Basic functionality to synchronize the strings and enums using C preprocessor macros.
* Updated all the custom convenience macros to work.
* Removed some duplicate update_tri_layer calls.
* Simplified the convenience accelerator macros for synchronizing enums and strings by removing the short enum names.
* Updated the CUSTOM_MACROS macro to use SS_LCTL instead of SS_LCTRL.
* Fixed a bug where the right side of the convenience layer in the Iris keymap was incorrectly listed twice.
* Removed the tenkey from the convenience layer. Added Windows 10 virtual desktop shortcuts to the convenience layer.
* Fixed a bug where the macro range was not set correctly.
* Added sigil values for the keycode enum so that additions to the sync macros will not require changes to the process_record_user ranges.
* Hacked send_string_P to work with ChibiOS boards.
* Switched to using I2C for the Iris keyboard.
* Finished a comment.
* Updated comments to explain that for non-AVR MCUs, the PROGMEM macro doesn't do anything.
* Updated the synchronization macros to use the more descriptive "NAME" instead of "CALL". Moved the Control-Alt-Delete chord macro to the synchronization macro.
* Simplified the custom macros by consolidating the macros into a context change macro instead of using alt-tab and minimize macros.
* Fixed a formatting issue where several tabs were used instead of 4 spaces.
* Added more comments to explain the synchronization macros.
* Simplified the PARAMS macro, since any parameters could be passed with a space by the declarer instead.
* Consolidated the synchronization macros into a single list. Simplified the synchronization mechanism.
* Removed the overloading macro, since it is no longer needed.
* Updated the convenience layer comments to reflect the changes made.
* Renamed the git_macros pointer table to custom_macros, since it no longer solely consists of git macros.
* Clarified that the send_string_P function's use of pgm_read_byte is different for AVR and non-AVR compilation targets.