#1 Improve Edit Lens Function

[Pantazis]

Couple of suggestions for the "Edit Lens" function.
1) Dialog "Defined Lens"
a. Add "Edit" button.
b. Change "Cancel" button label to "Done".
2) Dialog "Lens"
a. Add drop-down list of common focal lengths.
b. Allow selection of recommended CoC values from
chart, or make into a drop-down list.