Adds support for pausing recordings. When settings are eligible for
recordings, a pause button will appear next to the recording button. If
the settings are not eligible, it will warn the user in the output
settings that they cannot pause recordings if those settings are used.
This changes all of the icons from png to svg. With svgs, scaling is
unlimited. With the svgs, the issue of the @ symbols with the Windows
updater is no longer an issue.
I changed the colors of the icons to a light gray (#d2d2d2), in the
dark themes, because I thought they looked better with this color.
The mute, unmute, plus, minus, up, down and expand icons are from the
Feather Icons set. https://feathericons.com/
The visibility icon is from the Octicons set. https://octicons.github.com/
The locked and unlocked icons are from the Open Iconic set.
https://github.com/iconic/open-iconic
The system theme was named Default even though the default theme is Dark.
This addresses that by renaming Default.qss to System.qss. I've made it
backwards compatible so users already using this theme are not affected.
The theme list now shows up as:
-System
-Dark (Default)
-Acri
-Rachni
I have also made it so that you can specify the default theme in the
UI config file.
