audiobargraph_v: reorder
audiobargraph_v: simplify iec_scale
audiobargraph_v: simplify Close
audiobargraph_v: simplify Open
audiobargraph_v: cosmetics
audiobargraph_v: use NULL
audiobargraph_v: cosmetics
audiobargraph_v: simplify callback
audiobargraph_v: simplify parse_i_values
audiobargraph_v: simplify LoadImage
audiobargraph_a: silence debug
audiobargraph_v: use drawing primitives

4 times faster
4 times smaller
X times more readable
audiobargraph_v: more appropriate function name
Erase all the already read data in directsound buffer

Delays the apparition of #11145
audiobargraph_v: do not use Command variables
audiobargraph_v: use CFG_PREFIX