missing include <string>
Merge pull request #158 from rfree2/fix-include

missing include <string>
remove unused 'bitcoin-crypto' submodule
add crypto++ submodule and build
move to crypto++ zlib
move to crypto++ base64
replace openssl hash with cryptopp
ignore mac openssl deprecated-declarations
update travis to use system openssl on mac
port over to cryptopp pkcs5_pbkdf2_hmac_sha1
add base64 and zlib functions to OTCrypto.cpp
use C++ get password from prompt
add cryptopp aes support
cleanup otcrypto cryptopp api
temp