Create a scripted plugin loader

[kdvolder]

Create an 'initial' plugin-loader for client-side scripted plugins.

[kdvolder]

There is now a simple plugin loader for client-side scripted plugins.

Essentially, a client-side scripted plugin is an AMD module that gets autoloaded asynchronously by scripted when it starts up.

The module will appear to be a module with a name like this: scripted/plugins/<plugin-name>.

A plugin is a 'first class' citizen in the sense that it is really not any different from any other AMD module in the client-side scripted code. It can 'require' any other AMD module in the scripted and use the APIs on those modules.

Allthough technically a scripted plugin can load-up any existing client side AMD module with a require call, we don't want to encourage this. Instead the idea is to make specific 'nice to use' apis under 'scripted/api' that will be designed to make writing plugins for various interesting use cases relatively easy.

A few sample plugins already exist:

• copyright-plugin: Adds copyright headers on save if it detects the copyright header is missing.
• trailing-whitespace-pluging: Removes trailing white space on save
• zen-coding-plugin: Provides 'zen coding' edtitor actions and keybindings

Provisional apis currently available:

• 'scripted/api/editor-extensions':
  • allows creating editor actions across all scripted editor instances
  • allows registering 'preSave' transform functions that modify editor contents prior to save.
• 'scripted/api/keybinder': allows binding keystrokes to actions

There's much more work to do in cleaning up and fleshing out the loader architecture and the apis but we'll deal with those under separately tracked issues.