Some bug fixes and added icon and improve appereance.

 * Added icons to FA editor.
 * Disable not implemented buttons.
 * Clean project form old debug messages.
 * Refactor, repair and improve changing modes logic.
 * Repair NextStep and PrewStep functionality from unexpected SEGFAULT crashes.
 * Refactor and simplyfi RegExpToFA algorithm class.
 * Automatically select root RegExp node. (This very improve user confort.)
 * When changing mode to PlayMode regexp tree is cleaned.