Keyboard: Palm serial keyboard USB converter (#4485)

* Initial palm_usb support

* removing left over sun .c file

* fixing licenses

* actually adding updated files

* fixing build error

* more include cleanup

keyboards/converter/palm_usb/rules.mk

@@ -0,0 +1,46 @@
+MCU = atmega32u4       # Teensy 2.0
+F_CPU = 16000000
+ARCH = AVR8
+F_USB = $(F_CPU)
+
+# Interrupt driven control endpoint task
+OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINT
+
+BOOTLOADER = caterina
+
+# Build Options
+#   change to "no" to disable the options, or define them in the Makefile in 
+#   the appropriate keymap folder that will get included automatically
+#
+BOOTMAGIC_ENABLE = no       # Virtual DIP switch configuration(+1000)
+MOUSEKEY_ENABLE = no        # Mouse keys(+4700)
+EXTRAKEY_ENABLE = no       # Audio control and System control(+450)
+CONSOLE_ENABLE = yes         # Console for debug(+400)
+COMMAND_ENABLE = yes         # Commands for debug and configuration
+NKRO_ENABLE = no           # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+MIDI_ENABLE = no            # MIDI controls
+AUDIO_ENABLE = no           # Audio output on port C6
+UNICODE_ENABLE = no         # Unicode
+UNICODEMAP_ENABLE = no 
+BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
+RGBLIGHT_ENABLE = no        # Enable WS2812 RGB underlight. 
+CUSTOM_MATRIX = yes
+
+# Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
+SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
+
+#HARDWARE_SERIAL = yes
+
+SRC += matrix.c
+
+ifdef HARDWARE_SERIAL
+	# untested with palm_usb
+        SRC += protocol/serial_uart.c
+        OPT_DEFS += -DHARDWARE_SERIAL
+else
+        SRC += protocol/serial_soft.c
+endif
+
+DEFAULT_FOLDER = converter/palm_usb/stowaway
+