commented out legacy CertiKOS hypercalls, since they were doing an incorrect cast from a 32-bit integer to a pointer (which could be 64 bits)
updated kestrel_comm.c and kestrel_helpers.c to include latest changes from Kestrel versions of these files; factored out variable-length pointer arrays into two global macros; factored out mapping individual IVC buffer files into a separate function, map_ivc_buffer; wrote LynxSecure IVC communication functions
changed kestrel_certikosVM_ivc_finish_init to wait until the other VM has also set up its buffers for talking to us