setup.py: Add command for extracting translatable strings.
LinedConfigParser: internally use Unicode and return Unicode strings
FileChooser: internally use Unicode and return a Unicode result
Copyright year bump. Happy New Year!
MyConfigParser: retrieve and set string values as Unicode
Unicode: asUTF8Bytes -> less silly name "utf8"
Language: return Unicode strings even from dummyTranslator
MixStream: reorganize into a package
VideoPlayer: reorganize into a package
Config: remove log_ini_reads
Remove various reads of obsolete config keys.
Fix some incorrectly-named config gets.
GameResultsScene: don't use old jurgmode/jurgtype config keys
Resurrect some old config definitions that the code still uses.
Config: treat undefined gets as an error
Scorekeeper: remove obsolete partialStars property
Clean up some things found by pyflakes.
Remove the multi-scene-loading prevention hacks.
MixStream: Remove stream from channel table when _nextchunk fails.

This fixes a crash that sometimes happened in GameResultsScene when
the same SDL_mixer channel got reused for a sound.