Update 'make help' and add mac2caen to .PHONY

Makefile

@@ -213,8 +213,8 @@ EECS281 Advanced Makefile Help
            $$ make static
 
 * Mac to CAEN upload support
-    A) Requires an .ssh/config file with SSH Multiplexing enabled and an
-       open SSH connection.
+    A) Requires an .ssh/config file with a login.engin.umich.edu host
+       defined, SSH Multiplexing enabled, and an open SSH connection.
     B) Edit the REMOTE_BASEDIR variable if default is not preferred.
     C) Usage:
            $$ make mac2caen
@@ -252,6 +252,6 @@ help:
 ######################
 
 # these targets do not create any files
-.PHONY: all release debug profile static clean alltests partialsubmit fullsubmit help
+.PHONY: all release debug profile static clean alltests partialsubmit fullsubmit mac2caen help
 # disable built-in rules
 .SUFFIXES: