Update lang/pl_PL.lang

Fixed some typos and forms, updated missing strings. Checked for grammar and style mistakes.
Merge pull request #126 from copernic-us/patch-2

Update lang/pl_PL.lang
Merge branch 'master' of /ps3/showtime
Merge branch 'master' into chinese
add access to splitted files
modify a zh_CN translation item
Merge branch 'master' of /ps3/showtime
Merge branch 'master' into chinese