Make sure Cellfie window is not too big

[csnyulas]

Cellfie does not fit on some screens with low resolution. The biggest problem with this, is that some users may not see the buttons on the bottom of the Cellfie window, and (if they are beginners) they would not know how to execute their rules.
Tips for choosing the right size for Cellfie:

• Make sure that the Cellfie window that pops up fits the current screen.
• Since Cellfie is a tool available through Protégé, as a rule of thumb, it should not be (much) bigger than the Protégé window from which it is opened (the logic being that the user probably already set the Protégé window to a size that uses up a screen real estate that they are comfortable dedicating to Protégé related activities).
• Should not be bigger than the current default size (there is no point to creating a huge Cellfie window, even if there is space on the screen). People can still resize it, or even maximize it.