ENYO-2513, ENYO-2628: Top file selection in project's properties for the preview settings

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-2513, https://enyojs.atlassian.net/browse/ENYO-2528

* ENYO-2151 merging to reintegrate this branch to master
* FileChooser points on the related project directly
* Top file selection in project's properties for the preview settings
 * The file chooser cannot be set currently on the related project filetree, so the service has to be selected, and then, the project folder has to be retrieved.
 * Selecting the file, set the top file entry in the project preview tab.
* Continuous improvement:
 * i18n: https://enyojs.atlassian.net/browse/ENYO-1187
 * JSHint: https://enyojs.atlassian.net/browse/ENYO-2605
 * Image licence: https://enyojs.atlassian.net/browse/ENYO-2726

Checked on Windows 7 : Chrome

DO NOT MERGE

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com