Asset Database (BSON+SQLite3)

This commit begins the asset-db branch, which introduces the use of
BSON-backed blobs for a SQLite3 local asset storage database.

The objective of this branch is to provide an alternative to the Bundle
archives, which currently still rely upon external binary files.

This branch aims to be a transparent "plugin" for Alpaca's standard
asset management; later commits will modify the retrieval method(s) to
inject subsequent database reads to replace any values prefixed with
"sql:", where the remnant string is interpreted as an ID, thus allowing
the storage of binary data -- such as textures, vertex buffers, and
similar reusable blobs -- to be internally referenced.

NOTICE:
You *must* call Arpk::DB.connect_to() to establish a database connection
and perform subsequent operations!
Dependent Blob Injection

Prototype for injection of blobs upon which an asset depends.  This also
replaces the previous object initialization to a more direct manner,
thus ensuring that standard deserialization routines are NOT called.
Update README.md

Update readme for project dependencies of SQLite3 and BSON.
Improvements, documentation

Improves the DB.connect_to() method and adds additional documentation to
the module.  Improves the usage of DB.execute_update() and
DB.substitute().

This commit also adds a bootstrapper switch, --db filename, to
automagically load the plugin and connect to the specified database
file.
Query, Image improvements

Improves handling of queries, dependency injection of asset retrieval,
and adds the DB.get() method, which attempts to convert incoming blob
data to the appropriate type.

This commit also adds the ability to read incoming arrays of byte values
as an image.  Please note that this does not yet support Java array
types; arrays must first be unwrapped to be detected correctly.  A more
optimized solution is being investigated.
Blob type conversion improvement

Update to improve type conversions when the DB.get() method is called.
DB bugfixes

Fixes bugs in the handling of asset creation and dynamic subtypes.
Merge pull request #4 from fdurgn/asset-db

Confirmed.