norns 190930

norns 2.2.0

• NEW crow support
• FIX vu polls now use dbfs scaling @catfact
• FIX (BREAKING) audio.file_info() now uses absolute path
• NEW system_cmd async os call function
• NEW softcut level_slew_time slews level (not rec/pre level)
• FIX softcut level_slew_time -> recpre_slew_time
• NEW softcut pan_slew
• FIX softcut pan flip channels, scale from -1.0 (L) to 1.0 (R)
• FIX softcut level_cut_cut arg order @catfact
• FIX softcut equal power pan @catfact
• FIX softcut initialization @catfact