update Polish translation
fix lintian warning hyphen-used-as-minus-sign in man page
remove gmusicbrowser.menu (it is still in the debian folder)
fix bug involving gapless option and stop-after-this-song
update Korean translation
add thousand separator in most displayed numbers and some number-related changes

add ::__n translation function that replace %d in the translated plural string with the number using thousand separator
now uses MB for megabyte everywhere (some places used M)
now uses MB as 1000*1000 bytes everywhere (some places used 1024*1024)
simplify some translated strings
show unit for bitrate and sampling rate
various tiny fixes
add short description to some custom fields type
add way to edit "persistent" labels, and dialog to rename labels
add "new label" entry to the "edit labels" submenu