Show Wait modal prompt for all loading/saving

[birbilis]

Version: 0.7.7

Show Wait modal prompt at each load/save action, not just for loading from URL

Should also do when loading/saving from Options pane popup

Should also probably do when loading images/audio from a file (or url too in the future)

[birbilis]

implemented for MainForm's Load/Save, need to also do at Options dialog Load/Save (actually MainForm's Save calls Options dialog Save, so will need to do it once there)