Code reorganization

I'd wait until I completed reorganizing code, but I found some bugs that just had to be fixed (and a clunky way expression parsing worked) so I had to make this pull request earlier than I wanted...

* CODE: began reorganizing code
* Fixed a bug in expression parser (expression ending with an operator was not detected as erroneous)
* Fixed a bug introduced in 2.1.1.4 that prevented +/- key commands that (de)increment values from working completely
* Introduced a delay to value checking in dialog box, so that when user is typing, he does not get errors and warning immediately in process of typing
* Improved the way warnings are displayed in a label in dialog box