Refactor MultiSocket:
* Variadic constructor argument list
* Tidy up sources and filenames
base_uint now compares and assigns with beast::Zero.

Conflicts:
	src/ripple/types/api/base_uint.h
	src/ripple_basics/ripple_basics.h
Add Dockerfile:
* The ports are not automatically exposed.
* No test is performed after the build.
Check for openSSL version in SConstruct.
* Uses the platform specific openssl binary to detect the current version.