Added support for LiteCoin - tested and works
* factored out the check work from the block chain to the chain

Removed the last use of DB::matador

Added support for Ping->Pong and bumped up the protocol to 6.0
* Added heartbeat timer

ChatClient had a bug preventing it from connecting to the chat server - fixed
Way too many changes for one commit - sorry !

Tidied up in serialize, uint256 and util moving lock etc into until and making dependencies clearer.

Address: added possibility for a custom alphabet (for Ripple)

CBigNum added constructor for from *BIGNUM construction, bits() for bit length, and GCD operator (greatest common  denominator), ModPow and ModInverse for modular math
Merge branch 'master' of github.com:libcoin/libcoin