Update perspective.py

[silo65]

When setting perspectives, np.float on line 441 is called out as being depreciated. Switched to np.float64 to keep numpy scalar type float. If normal float is needed, use float instead of np.float64.

However, after implementing this fix, I am able to save and apply perspectives in the Perspective Configuration window, but when trying to Apply the perspective in the Superpaper Wallpaper Configuration window, it has an IndexError: list index out of range.

Error called out is:
superpaper_errors.log

[silo65]

After some additional testing, the new error seems to be with setting multiple span areas and trying to set custom perspectives. When all monitors are under the same span area (I only tested them under the default area 0), it works as expected.

My current setup is with 4 screens; 3x27" 1440p monitors horizontally level in landscape orientation, the left and right slightly turned in, and with a 55" 1080p TV centered above them. I want to have the 3 monitors (detected by the program as 0, 1, & 2) be on span area 0 and the TV on span area 1.