Use previous window position when toggling between mini and maxi mode

[neilenns]

Fixes #102

• Save the window position of mini mode window
• Use the bounds instead of size when toggling between mini and maxi mode
• Split the width breakpoint for resized mini mode and the default mini mode width into two numbers. This maintains the current small size for people have never used mini mode before but allows people to make the mini mode window wider to match vATIS if they want.

This works great in all my testing as long as both mini and maxi are on the same monitor. If you put mini on one monitor and maxi on the other monitor, and the monitors have different pixel densities, then the resizing and positioning doesn't work quite right. I can spend time in another PR trying to make that better, but it seemed edge case enough to not worry about adding complexity to fix it to this PR.

Here's the behaviour with this fix: