read file to recognise important function and mark

LibCallFromFile use LIBCALL_FILE environment to read file and constructe
the LibCallFunctionInfo Array

Signed-off-by: xiehuc <xiehuc@gmail.com>
add IgnoreFunc to keep the whole func

use environment IGNOREFUNC_FILE to set where to load
add mpi function to LibCall.txt

Signed-off-by: xiehuc <xiehuc@gmail.com>