add ability to specify different TINs for different stress periods

[Todd Wood]

In GMS, you can specify a time series or a TIN in the map module for a drain polygon. One GMS user would like to specify different TINs for different stress periods for drain elevations.

[Alan Lemon]

There will be an option in the next version of GMS (most likely called 9.1) to use a TIN with a transient data set. The TIN data set can also be in Date/time format and it will be mapped to the appropriate MODFLOW stress period.