handle list of plain FlatField's in createLayer

And, significant refactoring of code that converts python lists into
VisAD-friendly time sequences.  Not very Pythonic but at least the logic
is easier to follow now.

[1720]
Better way of handling results of IDV formulas
[1720]
Handle case where data is already a time seq.!

This should fix HP's forum issue ("1.5beta2: problem with createLayer")
once new installers are built.

[1720]
Handle case of plain FlatField with no time info
[1720]
[0] Dreamweaver updates synced from web server.