#10 Add config setting source codepage for old archive types

[Starikov Sergey]

I use xarchiver on UTF8 localized Linux workstation.
Sometimes I have to operate with old archive types (knowing nothing about codepage issue) containing NLS symbols.
It will be very nice, if xarchiver will provide feature for setting archive's codepage and recodeing symbolas from filenames in currect locale (meaning correct display in my currect terminal).

For example, almost all zip archives I receive are created on windows (meaning CP1251 codepage); .tgz archives are in legacy free *nix standard (KOI8-R in my case, other user may nedd other source locale, for example ISO...).
So, while opening or extracting files from zip archive I expect to see recore from cp1251 to utf8, and working with .tgz archive, from KOI8-R to UTF8.