* Password dialog is now scaled
* Background of lock screen is now scaled

ignoring return value of ‘fscanf’, declared with attribute warn_unused_result

This commit reverts:

https://github.com/mate-desktop/mate-screensaver/commit/816394c1a6ce9968dba3e1b0ecc884c8ccca4d43

And it applies an alternative to fix the deprecated functions:

gdk_screen_get_width
gdk_screen_get_height

revert 9075047d and update info a bit

fixes https://github.com/mate-desktop/mate-screensaver/issues/94