Handle Focus when Value is Removed

[envisionnw]

When a value is removed from one of the lower canopy fields on the point intercept data entry form, the form moves the focus so that the current point record appears at the top of the form. This does not happen when values are removed from any of the other fields (top canopy, soil surface, etc). We worked on this some just before the 2015 field season, and attempts to fix it seemed to uncover some other issues.