New Crimson.OpenSsl wrapper ontop of openssl (libcrypto)

This pull request adds support for a wrapper ontop of libcrypto which is part of openssl. This library is available on many platforms and is a good alternative to cyrptodev/ocf if not available. 

Here are some some early performance numbers on a linux VM running 4 proc (Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz):

    System.Security.Cryptography.SHA1Managed(8192): 107.814399509659 MBps
    Crimson.Security.Cryptography.SHA1Kernel, Crimson.CryptoDev(8192): 612.842682590854 MBps
    Crimson.Security.Cryptography.SHA1OpenSsl, Crimson.OpenSsl(8192): 691.377187029542 MBps

    System.Security.Cryptography.SHA256Managed(8192): 74.4333480199001 MBps
    Crimson.Security.Cryptography.SHA256Kernel, Crimson.CryptoDev(8192): 193.974164126646 MBps
    Crimson.Security.Cryptography.SHA256OpenSsl, Crimson.OpenSsl(8192): 250.835629355907 MBps

    System.Security.Cryptography.RijndaelManaged(8192): 40.5226021769138 MBps
    Crimson.Security.Cryptography.RijndaelKernel, Crimson.CryptoDev(8192): 386.965951981569 MBps
    Crimson.Security.Cryptography.RijndaelOpenSsl, Crimson.OpenSsl(8192): 461.553492233971 MBps

OpenSsl is 6X to 10X faster than managed, and ~20% faster than kernel crypto though Crimson.CryptoDev.

libcrypto also supports cryptodev (OCF) as an engine, but I've not explored this here.