use asm commons to drastically shrink code; eliminate Unsafe class that relies on Sun/Oracle private APIs; incidentally fix a bug where caught exceptions had to match declared type exactly, with no notion of inheritance, to be correctly rethrown

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/proxy/branches/version-2.0-work@1521303 13f79535-47bb-0310-9956-ffa450edef68