pocl_binary.c: implement the new binary interface
pocl_binary.c: implement the new binary interface

Also changes the binary format somewhat. Instead of saving
a single binary, now it saves program.bc and for every kernel
the entire contents of <pocl-cache-dir>/<hash>/<kernel-name>,
recursively.

dsandersimgtec/pocl,pavanky/pocl,franz/pocl,Oblomov/pocl,franz/pocl,dsandersimgtec/pocl,vkorhonen/pocl,pocl/pocl,jrprice/pocl,franz/pocl,vkorhonen/pocl,rjodin/pocl,pavanky/pocl,dsandersimgtec/pocl,franz/pocl,jrprice/pocl,pocl/pocl,rjodin/pocl,Oblomov/pocl,Oblomov/pocl,vkorhonen/pocl,rjodin/pocl,pocl/pocl,jrprice/pocl,pavanky/pocl,Oblomov/pocl,dsandersimgtec/pocl,rjodin/pocl,pocl/pocl,Oblomov/pocl,franz/pocl,vkorhonen/pocl,pavanky/pocl,pocl/pocl,jrprice/pocl