Add support for a module framework

[yestinj]

Add support for modules to InetVis.

Modules should be able to integrate with various portions of the application, for example a function could be called on the render hook.

This will allow the user to make use of modules that are most useful to them, and will allow developers to easily extend the application.

[yestinj]

Consider using a client - server architecture here. Modules could be the 'client', which integrate with the InetVis server component, using some sort of language agnostic serialisation, to allow modules to be written in any language.