display current volume level

See gh-55

example output:
```
02:08 [37%]  [=====================>                                    ] vol: 73%
```
display current volume level with graph

See gh-55

If the locale is UTF-8, display the current volume level as a graph:
```
02:08 [37%]  [=====================>                          ] [▁▂▃▄▅▆  ]
```

else fallback on displaying current volume level as text:
```
02:08 [37%]  [=====================>                          ] vol: 73%
```
Support non-ASCII search terms

Search query string (term including) is urlencoded before request.
Merge pull request #56 from thomasleveil/feature/display_volume

display volume when playing with mplayer
Merge branch '57' into develop
Show volume only when changed.
Remove graph characters
Resize progress bar when showing volume
pep8
Updated changelog
Update version number
Adjust column alignment
Update version number to 0.20.08 for release
Updated changelog for release