* Add provisional Helix implementation to test the quantum/split_common.
* copy keyboards/helix/serial.[ch] to quantum/split_common/
* Make serial.c a pure driver.
Remove buffer name and buffer size from serial.c. They should be placed in the caller(matrix.c, split_utils.c).
* remove quantum/split_common/serial_backward_compatibility.h
* Changed array serial_master_buffer to structure serial_m2s_buffer.
* Changed array serial_slave_buffer to structure serial_s2m_buffer.
* Change keyboards/miniaxe/matrix.c
I also made changes to quantum/split_comon/matrix.c to keyboards/miniaxe/matrix.c.
Note: I contacted @ka2hiro, creator of miniaxe, and I got permission to change keyboards/miniaxe/matrix.c.
* update history comment in quantum/split_common/serial.c
* Revert "Add provisional Helix implementation to test the quantum/split_common."
This reverts commit 168c82ef82c88e79979d9796bab9cc819cc2f685.
* fix keyboards/miniaxe/matrix.c, quantum/split_common/matrix.c
avr-gcc 4.9.[23] report error.
avr-gcc 5.4.0, avr-gcc 7.3.0 pass.
It is funny.
* update comment quantum/split_common/serial.c
* Reserve RGBLIGHT_SPLIT macro in quantum/split_common
* add temporary compile test shell script
* Extended support of SKIP_VERSION to make invariant compile results during testing.
* build_keyboard.mk, tmk_core/rules.mk: add LIB_SRC, QUANTUM_LIB_SRC support
Support compiled object enclosed in library.
e.g.
```
LIB_SRC += xxxx.c
xxxx.c --> xxxx.o ---> xxxx.a
```
* remove 'ifdef/ifndef USE_I2C' from quantum/split_common/{i2c|serial}.c
* add SKIP_DEBUG_INFO into tmk_core/rules.mk
When SKIP_DEBUG_INFO=yes is specified, do not use the -g option at compile time.
* tmk_core/rules.mk: Library object need -fno-lto
* add SKIP_DEBUG_INFO=yes
* remove temporary compile test shell script
* add '#define SOFT_SERIAL_PIN D0' to keyboards/lets_split/rev?/config.h
* quantum/split_common/serial.c: Changed not to use USE_I2C.
* Line ending stuff again
* Added Let's Split Eh? Files and updated #USE_IC2 checks to also include th EH revision (can only be used in I2C)
* Added personal keymap, updated some of the EH files
* Created new keyboard file for testing "lets_split_eh" will merge into lets_split once fully functional
* Added split code from lets_split, removed pro micro imports and LED code
THIS IS WORKING CODE, WITHOUT RGB AND BACKLIGHT
* Took back original Lets Slit files for the lets_split keyboard, working in the lets_split_eh folder for now
* Updated eh.c
* More rework of the I2C code, added global flags for split boards.
* Introduced RGB over I2C, having weird edge case issues at the moment though
* Fixed weird I2C edgecase with RGB, although still would like to track down route cause..
* Changed RGB keycodes (static ones) to activate on key-up instead of key-down to elimate weird ghosting issue over I2C
* Lots of changes, mainly externalized the Split keyboard code and added logic for only including when needed.
- Added makefile option "SPLIT_KEYBOARD" that when = yes will include the split keyboard files and custom matrix
- Split keyboard files placed into quantum/split_common/
- Added define option for config files "SPLIT_HAND_PIN" FOr using high/low pin to determine handedness, low = right hand, high = left hand
- Cleaned up split logic for RGB and Backlight so it is only exectuted / included when needed
* Updated documentation for the new makefile options and #defines specific to split keyboards
* Added a bit more info to docs, so people aren't confused
* Modifed Let's Split to use externalized code, also added left and right hand eeprom files to the split_common folder
* Removed some debugging from eh.c
* Small changes to keyboard configs. Also added a default keymap (just a copy of my that_canadian keymap).
* Added a README file to the Let's Split Eh?
* Changed it so RGB static updates are done on key-up ONLY for split boards rather than all boards. Also fixed leftover un-used variable in rgblight.c
* Updated default keymap and my keymap for Let's Split Eh? Updated the comments so it reflects RGB control, and removed audio functions.
* Fixed lets_split_eh not having a default version
* Removed "eh" references from lets_split folder for now
* Took lets_split folder from master to fix travis build errors, weird my local was overriding.
* Changed LAYOUT_ortho_4x12_kc -> LAYOUT_kc_ortho_4x12 to match bakingpy and others
* Removed rules.mk from my lets_split keymap, not needed
* Updated the config_options doc to better explain the usage of "#define SPLIT_HAND_PIN"
