Fix #IDEUI-197 ability to style part icon

Add needed decorateIcon method to TextEditorPartAdapter following
evolution of PartPresenter interface in ide.
Merge pull request #215 from stephanedaviet/IDEUI-197

Fix #IDEUI-197 ability to style part icon
IDEUI-142: add keypress event listener to the tree component.
Merge pull request #216 from codenvy/IDEUI-142

IDEUI-142: add keypress event listener to the tree component.