Renderer fix

Removal of dead code that should (and may) have been removed earlier.
Database updates

* Improves performance by generating a standard digest (rather than the
slower hexdigest)
* Adds a #keys() method that returns a list of all primary keys
* Allows for the #array() method to handle JSON data
* Adds a new configuration flag, :checksum_on_insert, which allows
enabling or disabling the generation of a checksum value when a new
value is inserted (depends on the checksum_key property; default: true)
* Improves the #include? and #store_blob() methods.

This commit also adds the missing "databases" property to the local.dat
database.
DB Transactions, Microphone

This commit adds a simple means to begin and end SQL transactions.

Furthermore, this commit adds the Arpk::Microphone object, which
represents a microphone-in line on the host machine.  In "push-to-talk"
mode, the microphone only broadcasts to its output line so long as it is
not muted; otherwise, samples must exceed a noise floor of 15 dB
(default, may be specified).

To broadcast captured sound, you must specify the output line via
#line_out=
Microphon multi-output update

This commit changes the @line_out attribute of a Microphone to an Array,
which may contain multiple instances of IO, OutputStream, or Line
objects (and their subclasses).

The new methods #broadcast(), #broadcasting?() and #remove() manage
adding, testing, and removing lines from the list, respectively.
Calling #destroy() will terminate the Microphone's runtime and destroy
all open lines (@line_in and @line_out).
Allow reading from JAR archive

As an alternative to using the DB framework to package assets into
SQLite databases, this commit adds preliminary support for reading
resources from JAR archive files.

This commit also adds the Arpk::Toolkit reference, which points to the
value of java.awt.Toolkit.getDefaultToolkit().
Built-in resource loading

Allows for resources and assets to be loaded from JAR files a similar
manner to how they are extracted from the database.
Convert to using JARs as default

This commit converts the engine to use various JAR files and a cache of
resources held within them (see Arpk::Resources in lib/utils.rb).

In addition to expanding upon previous abilities to load resources from
JAR files, this commit also adds the ability to load resources by their
name from any JAR file present in the data/ directory so long as a
request to a supporting method begins with either "res://" or "@".

Please note that you may also explicitly reference the URI of a resource
via its full or partial path by naming its containing JAR file (ex:
"path/example.jar!MyResource").  This is the same format returned via
Resources.find().
Merge pull request #6 from florf/db-plugin

Confirmed.
Merge remote-tracking branch 'origin/development'