Parts of the code are unnecessary and slow

[Umang Varma]

Some parts of the back-end and GUI are slow and perform some tasks more often than required (e.g. updating the labels). This reduces performance and code standards.
Some examples:

 * App.__update_words is used too often (often not required)
 * anagram.guess doesn't return whether the word has already been typed in or not. Once the anagram class starts tracking score also, then this will be check twice instead of once

More such issues should, of course, be weeded out before 0.1.2, since they are relatively trivial cases.

Any changes in the back-end should be reflected in the unit tests!

[Umang Varma (umang)]

Though the two mentioned originally have actually been fixed, this bug with the impression that a lot could be done. After actually using timeit to see if there is any difference, it turns out that there is no visible difference.

Maybe I should have listened to Mark Pilgrim (http://www.diveintopython.org/performance_tuning/summary.html)!

[Umang Varma (umang)]

(typo)
*this bug was filed with the impression