fix crash when reading maxage pref

an EditTextPreference will always return a String, so getInt() causes a
ClassCastException.  The EditTextPreference for maxage needs to be
retreived as a String, then converted.  It is first converted to a Float,
in case the user has entered in a decimal, and that is then forced to an
int value.
print full stack trace of caught exceptions to aid debugging

Also, use the short name in the TAG so its easier to read which class the
error is happening in.  with getCanonicalName(), it includes the whole
package name, then you need a very wide column to read which class the
text is coming from.
KerplappRepo: close apkJar on problems to prevent leaks

Eclipse was warning me, so I added this little fix.