widget: Fix a drawing artifact with blinking cursor

https://bugzilla.gnome.org/show_bug.cgi?id=731427
(cherry picked from commit 977375b05df4f906329177a401a2d8c00b2516d4)
utils: Set some FS flags on our temp files

Disable COW on our temp files, if the FS it's on supports it.

(cherry picked from commit 4b4cb33957749a2f194aeec63c1b17b4acd29c02)
Version 0.36.3
Post release version bump