Added a collection of DIAG_X booleans to hexRef
Allows the use of the diagLevelDict to much greater effect,
setting diagnostic messages on/off by function or area of code.
As before, if the dictionary file is not found, or does not
contain the relevant variable, the bool defaults to false,
and the messages will not be displayed, cutting down on lots of
verbose text during running, which is likely obstructive and
unhelpful for others.
Some further changes (in particular to DIAG_SetRefinement) might
be made, to narrow down the amount of text dependent on just one
variable. However, I want to avoid creating too many more bools,
since there are 17 in this commit, replacing the functions
previously given by 'debug' and 'extended_debug'.
'extended_debug' has been removed, so can no longer be set from
a solver, but if you wanted to change things, setting the
read option of the dictionary to 'MUST_READ_IF_MODIFIED' is
possible