Integration of multiple changes

Merge important changes :

* **mikezackles :** Daemonzing bitmonerod (background start, bitcoind-like cmds/communication)
* **tewinget :** Splitting 'simplewallet' (cli+rpc) into two entities -> *simplewallet* (cli) and a more robust *rpcwallet* (rpc).
* **tewinget :** Transaction splitting when too big (will ask user confirmation in *simplewallet*)
* **neozaru :** *wallet2.h* wrapper usable as C++ library

Devs, please check I haven't fucked something.
I tested both branches separately (excluding tx splitting), then I tested very quickly after merging.

Note : 'msg_writers' in simplewallet.cpp have been removed by pre-auto-merge, so I adapted 'msg_writer() << **' functions. Let me know if there is something wrong.

Testers are welcome.