Adding in atomics. Added in unit tests and also necessary files to build
linux .so and static.

Change-Id: I97792fd2c50e100ac8f1cb732db541c7829b366c
Reviewed-on: http://www.matthewh.me/gerrit/32
Reviewed-by: Matthew Hoggan <mehoggan@gmail.com>
Tested-by: Matthew Hoggan <mehoggan@gmail.com>