Crypto++ 5.6.2 released

The release notes for Crypto++ 5.6.2 follows. changed license to Boost Software License 1.0 added SHA-3 (Keccak) updated DSA to FIPS 186-3 (see DSA2 class) fixed Blowfish minimum keylength to be 4 bytes (32 bits) fixed Salsa validation failure when compiling with GCC 4.6 fixed infinite recursion wh