rewrite of OTData api using STL and C++11

This pull request contains a full rewrite of the 'OTData' API.

In my work on adding Crypto++ support to OT, OTData came to my attention as something that needed lots of work.  So here we are with a new data type for Open Transactions, based upon STL.

Please review this code, the changes are very large, and effect lots of files; in-particular OTCryptoOpenSSL.cpp

This pull request will need lots of regression testing, as many many files in this project are touched.

Cam.