Rollup

-ZLib and GZip compression support for chunk data and NBT data (see
compression.hpp) (introduces dependency on zlib).
-RSA key generation/encryption/decryption support (see rsa_key.hpp)
building up to protocol encryption support (introduces dependency on
OpenSSL).
-Added Chunk class.
-Changed DataProvider interface to reflect reality of biomes (stored
per-column not per-chunk).
-Updated build script so it's a bit more readable.
-Added "instructions.txt" with some links I found useful in
downloading/building/using zlib and OpenSSL (on Windows).
-Moved test/sanity check code into "test.cpp" so I can start writing an
actual server bootstrap in "main.cpp".
-Started to add chunk serialization/deserialization support for packet
0x33 to packet.hpp (unfinished/untested).