Syjun/vecphys emprocess fixed rb

This is an updated branch of vecphys-emprocess-fixed which includes

1. additional fixes for remaining warnings of unused parameter/variable
2. revert auto -> int for associated compilation errors from Vc
3. resolve conflicts with the HEAD (similar fixes for unused parameter already committed by Federico earlier)
4. remove unnecessary options and variables from vecphys CMakeLists.txt (taken from fca/vecphs)