Buffers in message parsing API
Added find_node message
Forgot to add files to previous commit
Minor improvements to messages
A lot of changes I don't want to split

Merged Peer into Node
Changed Callback APIs
Removed inlines
RoutingTable message handling implementation started
Added some comments
Callbacks payload is a type and optional

Callback arguments are now passed in a type encapsulating them.
This allows to increase the parameters or to send none in case of
an error or timeout.
The internals are using boost::tuple.
A lot of stuff, I should have done more commits :(

Fixed bug: unordered buckets in the set

Routing tables functions are now split in 2 files
Added Yield util class
getClosestNode in NodeTree implemented for find_node
Distance operator moved to NodeData
Added comments and doc
findBucket in NodeTree is now O(log n) thanks to the bugfix
field_node implementation
Removed boost libraries in favor of std

- smart pointers
- foreach
- tuple
- mutex
- thread
Buffer -> std::vector and major fixes

- DHT bootstrap from network is "working"
- Buffer class is something less insane
- Messages are properly received
- Replies must have a validator or have their own class, still to decide
Removed regexp as a dependency for the main lib
fixed spaces
Created namespace/classes for query/reply

Also fixed a little bit the callback system
Fixes to find_node messages