Status: Make symbolic audio icons bigger

[newhoa]

New symbolic audio icons to make size of status / systray icons more consistent.
Also uses the new strikethrough style for muted and blocking.

Addresses part of #152

Current:

Proposed:

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This PR uses this style for audio-volume-muted-symbolic and audio-volume-muted-blocking-symbolic:

Here is an alternative, more like what upstream uses. When you go from audo low to mute, the icon "jumps" more (the speaker icon goes from left to center) and to me is a little less legible (the strikethrough sort of blocks what is behind it). But, it is cleaner looking:

Up to you on what looks better, I don't have a strong feeling either way. Here are the SVGs if you want to try them in-use.

[ochosi]

Same question as for the wifi icon - how does upstream solve this problem?

[newhoa]

Upstream went with the rounded speaker a bit ago, but it changed the way the icons are positioned and the bars appear. You can see between their high and low that the icon is always centered, with one of the "loudness bars" removed in each lowered state. So the speaker shifts from the middle at low or off to the far left when full, with the bars moving position each time as well. In the Xfce panel and a lot of apps, at least, it meant the icon shifted with every volume state which didn't feel very smooth.

So this was kind of a compromise between upstream and our current one, while also trying to fix the size consistency problems in #152.

Fixing the size consistency meant making the speaker bigger. I think it makes the speaker easier to see and looks a little more balanced on each side or overall and fits in better with the others with this look... but it did leave less room for the bars. So I did need to reduce the curviness a little, not sure if I did that well enough or if they look quite as clear. That was the hard part on this that I don't know if I got good enough. Any feedback would be appreciated!

[ochosi]

Oh wow, wasn't aware of the upstream speaker changes!
These small icons are always a bit of a compromise, I think you did a great job and keeping the thing centered is certainly a win!