Remove limit on pupil size

[shbonita]

Right now there is a limit of 3.5mm for pupil size to be included as part of a fixation. We should remove this restriction. There should be no upper limit.

[Joshua2000B]

Because of the slider GUI, an upper limit is needed until the GUI can be rewritten. For now, the upper limit has been increased to 10.0 in commit 164e0cc