Replace old proposal tables
I deleted the old PROPOSAL tables and replaced them with the tables for the new version. I added two versions of each file (gcc and clang), which will be the solution until I fixed the hashing issue in PROPOSAL.
For now, these are the tables for electrons, positrons and photons for a 60 GeV cut, so that the em_shower
example will run without creating any new tables.
(This is related to issue #426)