Add the ability to override the default ID3v1 string handling in TagLib by

Add the ability to override the default ID3v1 string handling in TagLib by
adding a ID3v1::StringHandler class that has render and parse methods.

By default this still makes the (correct) assumption that ID3v1 tags contain
ISO-8859-1 data, but this makes it easy for applications to override this to
allow user specified codecs.

CCMAIL:78428@bugs.kde.org
CCMAIL:77710@bugs.kde.org
CCMAIL:amarok-devel@lists.sourceforge.net
CCMAIL:Shlomi Loubaton <loubaton.shlomi@012.net.il>
CCMAIL:Nir Misgav <misgav@ee.bgu.ac.il>

git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@301244 283d02a7-25f6-0310-bc7c-ecb5cbfe19da