ENYO-2106: plugin depends on `%PLUGINDIR%`, not on `%INSTALLDIR%`

- it is up to Ares to locate the plugin & provide the `%PLUGINDIR%`
  value to the plugin configuration.  The plugin can then load its
  resources relatively from its installation root folder.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-2106: globally use `myDir` instead of `__dirname`

It seems like `__dirname` is not defined in node-webkit.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-2106: substitute `%PLUGINDIR%`

This is the first variable whose value is plugin-dependent (others are
platform-wide).  So the code needed a small refactoring.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-2106: rename ide.json into ide.plugin.json

The is the simplest way I found to make sure that Ares does not consider
its own `ide.json` as a plugin configuration file when both Ares & its
plugins are installed as similar modules using NPM.

This change demands (of course) the dual change in plugin's source.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
ENYO-2106: move ares-ide manual wrappers from plugin into ares-project

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>
Merge branch 'master' of github.com:enyojs/ares-project into ENYO-2106
Merge pull request #279 from enyojs/ENYO-2106

ENYO-2106: make packaging easier

Tested on Debian/linux with chrome