Playback speed default settings

[neilquinn]

1. It would be nice to be able to select my own 3 default playback settings. Right now they are 1.0, 2.0, and 3.0, but 3.0 is almost never used.

On overcast for example I tend to prefer 1.0, 1.5, 2.0, or if I had 4 choices I'd add 1.25 in there.

2. Have +/- button change in increments of 0.25. No one can tell the difference in 0.1, and definitely not the difference of 0.05 !!!

Right now I'm forced to go to 1.0 and then tap ten times on every book to move it from 1.0 -> 1.5 (why is it in such granual 0.05 increments?!?)

While this is somewhat similar to issue #852 , I am asking for better defaults and larger increments. That issue is also 3 years old.