Implement an interpreter for template previewing

[rydnr]

Information

The current mechanism to debug templates is making use of ST4's Template.inspect(). It eats up all available memory. Additionally, the way it's implemented right now is not particularly helpful.

Instead, a "template development service" should be invoked, passing the template and context as arguments.
A "server" would implement that interface and be resolved via JDK6's services. Such server would, using netty, listen for external commands using a REST api.
A command-line client would send commands such as "reload", "next table", "previous table", "next template", "previous template".

Actions required

• Refactor AbstractTemplate to use a TemplateDevelopmentService instead of Template.inspect().
• Create a LocalTemplateInspectService implementation to call Template.inspect().
• Create a RestTemplateDevService implementation to accept commands via http.
• Create a command-line client to send commands via REST.

Steps to reproduce

• N/A

Acceptance criteria

• N/A