Connection Shared Code

Added shared -- i.e. platform-agnostic -- code to the Connection object.
SendState to Shared Network Header

Moved the SendState enumeration to the shared network.hpp header, from the platform-specific network/windows.hpp header.
Network Bugfixes

Fixed a bug which was causing odd behaviour on accepted connections.  After getting a completed accept initiated with AcceptEx, setsockopt with SO_UPDATE_ACCEPT_CONTEXT was not called, causing odd behaviour (most notably that calling shutdown on the socket would fail).

Fixed an oversight which caused error messages returned by GetErrorMessage to have a trailing CRLF.

Added comments to the GetErrorMessage function.
Data Provider Settings Helper

Added a helper member function template to the DataProvider abstract class which allows settings to be retrieved parsed to certain types.  Alternately, if the setting does not exist, or could not be parsed to the type-in-question, a default will be returned.

This will allow for a tremendous reduction in boilerplate code when fetching settings.
Network Rewrite Integration

Integrated the new network stack/interface into mcpp.dll.

A bit of refactoring was required since the name of one of the event types from the new network stack collided with the name of the class which represented packet receive events.  The offending type was renamed to "PacketEvent".

Refactored the server startup code quite substantially.
Handshake/Ping Updates

Updated the modules which handle handshake and server status to refer to "PacketEvent" rather than "ReceiveEvent".
Makefile Update

Rolling several makefile changes into one commit:

Changes to compile the new network stack into mcpp.dll.

Changes to compile the authentication API (since that was split out of the actual vanilla minecraft.net authentication module).