[REFACTORING] Model and Coercer generators' templates refactored.
[FEATURE] Option -d added to Domain generator for selecting dummy db adapter.

  $ hexx domain -d pg
  # uses postgresql for the dummy instead of sqlite3

== Changes

* Generators::Core - selects corresponding dependency in gemspec.
* Generators::Specs - selects corresponding adapter.
* Generators::Dummy - manages -d option for Core and Specs.

== Version

v0.3.0 (unstable, backward-compatible) released.