Make script executable
Fix exception handling
Remove stale voiceover files to save space
Add installation steps for Gentoo
Support voiceover for Russian files

Use RHVoice to generate voiceover for Russian files and pico2wave for
all other files.
Detect Russian file names using a simple regexp.

Assume iPod is mounted using utf8 instead of latin-1 codepage to allow
Russian file names. (long file names are UTF-16 on disk anyway)
Add argument to set volume gain for all tracks

Partially revert 8b38b0fb90101a44a10573daa5c29f582dca0553 to set default
volume gain to 0 instead of 60 (which is extremely loud for my ears with
my headphones).
Update README with --track-gain argument