Refactorizations, fixes #44, #35, #34, #25

[Krigpl]

Refactorization of keyboard shortcuts: all shortcuts are now in separate class.
Refactorization of parsers: adding a new task/contest parser should be neater now.
Refactorization of execution results: chenged execution results to Enum. Adding new execution result requires less code now.
#25: All windows appear in the center of previous window.
#34: Right click on the problem tab and the option "delete" will appear.
#35: There are two abort buttons now: abort current test and abort all tests. Both work fine.
#44: Copy input button added. With shortcut ctrl+shift+c.

Other changes:

• Time limit is now editable. And task parser for Codeforces extract and set time limit for all tests.
• alt+[1-9] switches between problems.
• Added tool tip to parsing result label. Moving cursor over "parsing failed" shows message with exact parsing error.

[dj3500]

This is looking really great!
Just a few things:

1. aborting tests doesn't work for me (with a program "int main () { while(1); }", "abort current test" does nothing, and "abort all tests" does nothing to the current test but prevents further ones from running after the current one TLEs
2. in "new problem" dialog, if user set their own problem name and then pasted the URL and clicked "Parse", the name should not get overwritten by the parser
3. what does "NOT18N" mean?

[Krigpl]

1. Fixed. That was stupid bug and my tests were weird that they did not detected this.
2. Fixed.
3. I don't know. Netbeans auto-generated that at some point, don't know why.

[dj3500]

In 2: When I set my own name and then parse (or first parse and then set own name), my name stays in the "Name" textfield but is still overwritten in the actual name of the tab that gets created.

[Krigpl]

Fixed. Sorry about that.

[dj3500]

Awesome!