Fix typo.
Use the recently defined macros instead of using the
traditional PicoC-style defines for the platform
variables. (For examples, check lcd.c).
Added support for PicoC in the I2C platform
module. Now, the PicoC and Lua parts of the
I2C module coexist in src/modules/i2c.c

Added a few TODO's for the I2C module.
(variadic functions). Let us get to this
later.