Option to increase maximum number of iterations for makeWellTS?

makeWellTS returns a message indicating any problems with convergence (also, perhaps that should be `message()` rather than `print()`?).

Code 1 reflects the fact that the maximum number of iterations have been reached before convergence (According to the `optim` documentation). What about an argument allowing the user to pass options via `optim.control` in the call to `StructTS`? This should allow users to increase the maximum number of iterations if they need to.

Locate makeWellTS and inspect its call to StructTS, then read the optim and optim.control documentation to understand the available settings. Done means users can provide control options for the iteration limit and the convergence result is reported consistently, including whether message() should replace print().

Written by the indexing model from the issue text.