RQDA 0.1-9

* widgets are enabled only if they are usable.
* Better code categories management system and various improvements of GUI.
* Click-handler for second half of code-mark.
* Better default color scheme for code mark.
* New function of and().
* New option "both" in "type of retrieval".
* New option of subset in GetAtrr().
* It can handle ' correctly now.
* Upgrade RGtk2 (>=2.12.12).
* Various bugfixes.
