export window too small, not expandable

[wolftune]

When exporting, the number of items to choose from is huge, and the window can't be expanded, so it requires excessive scrolling.

The real issue is if the categories pane is active when choosing to export, I can switch in that window to the tasks pane for export, but that means the window is even smaller.

Window size if category pane is active when choosing export:

Window size if task pane is active:

(noticed this testing status on an old export bug)

[realcarbonneau]

Fixed. I set the windows size explicitly and set it to be resizable and made the inner controls grow as needed during resize.

v2.0.1.46 - Datetime and duration refactor continued, divider fix, export window fix
https://github.com/taskcoach/taskcoach/releases/tag/v2.0.1.46

Datetime and duration refactor continued, divider fix, export window fix #294