Added accelerometer and pressure drivers for white PCB, and new modules.

[HashakGik]

My fork fixes issues #11 and #20 and defines the constants WHITE_PCB and BLACK_PCB for easier management of modules compatibility between the two eZ430-Chronos hardware versions.

Some new modules are added as well (see README.md).

[BenjaminSoelberg]

Hi HashakGik.

What a great pull request!

Thank you for all your great work

I look forward to fold your work into the master branch.

Feel free to keep them coming :-)

[BenjaminSoelberg]

(im working on adding the circle ci v2 build system to this project after the sunset of v1.0)

[HashakGik]

I'm glad you appreciate it.

A couple of things you should bear in mind when merging my fork:

• I had to edit the makefile in order to compile on my system (Slackware Linux) and I lost track of what I changed for my toolchain and what is actually required for the new drivers and modules (I remember only the -lm linker flag, required by the accelerometer and boiling point modules (the drivers DON'T require the math library); I'm sorry but apparently I forgot how to write reasonably fast log10, sqrt and atan2 functions so I had to link the entire math.h)
• Emacs messed with the indentation of the files I edited, so in order to make things consistent, I indented everything in Kernighan-Ritchie style. I hope this isn't a problem.
• I own only a WHITE PCB eZ-Chronos, not a BLACK one, so I can't guarantee my code doesn't break anything on black PCB watches.

About future commits I thing I'm going to take a looooooong pause: to preserve my sanity I had to give up making the SimpliciTI library work (on my local copy I made little to no progress from commit 2b32e7b , so it's not worth pushing it) due to the inhability to debug it (the code won't fit in the watch if compiled with -O0 and the watch behaves differently when connected to the debugger, even when compiled with -Os).

[carlosgonz0]

Will this PR merged?