Support for "Revisioned" Models

This primarily adds support for models that use "release:*" tags that are used to defined revisioned entities (e.g. Widget and WidgetRevision). With a new "Released" transform, it can create an alternate data model by merging object/revision entities into a single "released" entity. This makes it useful for clients that want to view all data with respect to a single release without having to deal with revisions.

v0.15.0

The install instruction changed to require files being installed to have the .eml extension - in addition to the file's native extension. For example, SomeSourceFile.java.eml. After using $[install "SomeSourceFile.java" "somedir"] it will be installed as SomeSourceFile.java`.

A new assert instruction was added to make it easier to generate error messaging (see docs).

Fixed schema/database bug

Fixed an issue with the Postgres transform not writing out its schema file properly thus making the subsequent generated SQL versions incorrect.

New Command Line

The original command line was not scaling very well and not very intuitive. I decided to adopt the command line style from git where it starts with a command. This allows the features to be nicely partitioned and organized.

Maven project

This release includes the ability to build the project with Maven. See the README.md file in the Building and Running section.

First as Open Source

This is the first release since going Open Source.