* libi2c/libi2c.c, libi2c/libi2c.h, libi2c/README_libi2c:
Added checks so that use of 'stdio' is avoided (falling
back to 'printk') before the system is up.
Publish driver entry points so that the libi2c driver could
be added to the applications 'device driver table'.
This is not fully implemented yet, though, since in addition to
initializing libi2c the low-level i2c bus drivers as well
as high-level i2c device drivers need to be registered
with the library.
Updated README_libi2c accordingly.
* libi2c/Makefile.am, libi2c/Makefile.in, libi2c/libi2c.c,
libi2c/libi2c.h: New files.
* Makefile.am, configure.ac, preinstall.am, wrapup/Makefile.am: added a
simple API/library for i2c devices and drivers for i2c 2-byte eeproms
and a ds1621 temperature sensor; API is documented in libi2c.h
