Improving Ruby's Synchronization Primitives and Core Libraries

This RubySoC project is divided in two parts. Both are intended to 1)
give Ruby some more features and 2) make it faster, both be improving
Ruby core code and writing C extensions when possible.

The first one is related to Synchronization Primitives, data
structures that are very useful and necessary while programming
multi-thread/processes systems. Ruby has some synchronization
primitives implemented on its core, and others can be found in several
different Ruby-only gems and libraries. Some of these primitives could
have their Ruby code polished, and others could be sped up by a C
extension. The objective of this part of this project is to improve,
where possible, Ruby code of existing synchronization primitives
implementations and to improve their efficiency by writing C
extensions for the most important and useful ones.

The second part is related to Ruby core libraries. It's known that
there are lots little improvements to be done on core libraries that
could improve Ruby efficiency and code readability. Even more could be
done to improve speed by writing more core code in C. There's a lot of
work to be done here, and the objective of this second part is to
improve as much as possible Ruby core by polishing Ruby code and
improving more C extensions.