Files List component: improve buttons

[Oliver Kusche]

• disable start button while files list is empty
• make buttons larger, add icons

[Oliver Kusche]

use these icons (in resources/icons)

[Oliver Kusche]

The buttons are rendered okay on Windows, but not correctly on Mac OS X on a Retina display. This is mainly due to the lack of SWT support. Needs to be investigated and fixed.

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=382972 and http://de.slideshare.net/da152/swt-scalingece2014-aktuell

[Oliver Kusche]

Solved for now by changing button style to SWT.FLAT. Needs to be revisited once Bug 382972 (see above) has been resolved.