Move SleepFor function to common as it is pretty common thing to use.

At the same properly update all the examples to link to remus common, so
that they get the proper includes for the SleepFor functions, as they are
going to move to use boost soon enough.

Change-Id: Iab5a821793a737acaada13f8130db78b737a53eb
Merge pull request #60 from robertmaynard/proper_boost_includes

Move SleepFor function to common as it is pretty common thing to use.