Fix handling of invalid encoded =xy sequences. In particular, the following cases are now handled gracefully, that is the characters are output as is: - =ap (fixed by introducing mLastChar) - ==\n (fixed by handling the case mBadChar == '=' correctly) - =\s (fixed by don't restricting which mBadChar is output; only exception is '=') - =\EOF (fixed by correctly implementing ::finish()) - =a\EOF ( " ) - ==\EOF ( " )

Now this codec actually passes all the tests which don't involve trailing whitespace.

svn path=/trunk/KDE/kdepim/libkmime/; revision=466541