added load and save functionality for training programs

[daanvanhasselt]

Added buttons for saving and loading training programs in the UI. Show a Windows file dialog for either picking a file to load or picking a location to save to. Note: if RL is fullscreen this acts kind of funny and you have to alt-tab a bit to get around. In windowed mode everything is fine.

[daanvanhasselt]

5

[Timmeey86]

It works in general, but there are a few things I'd change:

• It would be more beneficial to save and load single training programs only, since the most common use case will be one player/coach creating a training program, exporting it and supplying it to others. Loading a full training program list would also override your workshop map path, for example
• I had to type in '.' into the file load dialog in order to see the file I exported to. It would be nice to be able to have our own file format like .rltt or something, or use *.json as a default filter

[daanvanhasselt]

• I added the ability to save individual training programs and loading a single training program from a json file
• The supported file types (json) are now displayed in the filetype filter dropdown
• If no extension is supplied when saving, .json is automatically appended