Added extra theories to examples/miller.

Put src/probability in build-sequence; change Miller example to cope.

Changes are necessary because the HurdUseful that the Miller example depends on no longer has REVERSE in its API.

Reorganise files under examples/miller.

In particular, combine formalizeUseful, subTypeUseful and
ho_proverUseful into one HurdUseful that is in its own directory.
Also, put Know and Suff tactics into that library so that they don't
need to be repeatedly redefined at the head of the various Script
files.

Move examples/miller/RSA up to examples/ (replacing older RSA there)

This removes some unnecessary redundancy in examples: the two copies
of RSA are mostly identical.

In examples/miller.
Remove the selftest.exe and m shell-scripts, replacing them with
Holmakefiles that use INCLUDES options to ensure that directories
are built in the correct order.

Also keep the --qof flag effect by the OPTIONS = QUIT_ON_FAILURE
line.

Fix one problem in the measureScript.sml file (caused by
parse_in_context's new pickiness), and fix the absence of the new
name field in SSFRAGs in extra_pred_setTools.