Constification part 3.
Constify parameters of instrumentation functions and callbacks from
VexTranslateArgs.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2958 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Constification part 4.
Constify pointer typed members of VexTanslateArgs.
Fix ripple.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2959 8f6e269a-dfd6-0310-a8e1-e2731360e62c