lua inbinary strings

Allows saving of ram by reusing strings already stored in the binary
and storing a pointer instead of malloc and copy to get them inside
the lua state

Saves about 1.5K overall

Derivative of work by bogdanm
RAM optimizations: pseudo RO strings, functions in Flash
https://github.com/elua/elua/commit/d54659b5723bcd2b1e3900362398c72c18a9aa0b

Change-Id: I21d6dcfa32523877efd9f70fb0f88f2a02872649
10 files changed