Make it possible to load multiple plugins from a single plugin.js file

[Martin Kou]

This feature request came from Senthil Kumaran of Oracle.

It is possible for some CKEditor users to have a lot of custom plugins written inside a single plugin.js file. Right now it is impossible for CKEditor to do so because even if you've defined a number of plugins pointing to the same path, like:

CKEDITOR.plugins.addExternal( 'my_plugin_1', 'file:///c:/my_plugins/' );
CKEDITOR.plugins.addExternal( 'my_plugin_2', 'file:///c:/my_plugins/' );
CKEDITOR.plugins.addExternal( 'my_plugin_3', 'file:///c:/my_plugins/' );
CKEDITOR.plugins.addExternal( 'my_plugin_4', 'file:///c:/my_plugins/' );

And instructed the editor to initialize all of them:

config.plugins += ',my_plugin_1,my_plugin_2,my_plugin_3,my_plugin_4';

The editor would still only initialize one of the plugins, because it thinks it has already done the initialization for ​file:///c:/my_plugins/plugin.js after the first init() call. Subsequent plugin initializations are ignored right now.

[Martin Kou]

In the conference with Senthil yesterday, he also expressed that he wished to see something like this:

CKEDITOR.plugins.addExternal( 'my_plugin_1,my_plugin_2,my_plugin_3,my_plugin_4', 'file:///c:/my_plugins' );

Instead of having to write an addExternal() line for every plugin in a file.

[Frederico Caldeira Knabben]

The patch includes changes to config.js, with I believe (I hope actually) are testing stuff that ended up into it by mistake.

Other than the config.js changes, the rest is ok and can be committed.

[Martin Kou]

Fixed with [3069]. All changes in config.js are removed from the commit.