Make libmbox build with -DQT_NO_CAST_FROM_ASCII
- use QLatin1String() for literals
- QString::fromLatin1() when converting a QByteArray for use with QRegExp
- QString::fromLocal8Bit() when converting an encoded file name
svn path=/trunk/KDE/kdepim/runtime/resources/mbox/libmbox/; revision=1064202