licenses: convert license tags to SPDX

lib: various crunch improvements

The main one is that crunch now uses wpsimp when determining whether a goal
can already be solved, instead of just wp. Crunch can also now use wps
when proving a goal and will now always ignore a constant if told to, even
if it is the top-level constant being crunched.

lib: improve the parser for crunch.

The main benefit of this is that everything in crunch is now ctrl clickable.
As an added benefit, supplied rules can now be modified by attributes when
needed.

lib: Refactor crunch so that it can be used for both the nondet monad and the trace monad

lib: improved crunch

The main aim of this is for crunch to make consistent decisions about
whether to prove new rules. If any rules in the wp set can be used to
directly solve the goal crunch is working on, then crunch will just
use it.

Other changes include:
- crunch_ignore works properly inside locales again.
- if a rule already exists with the specific name crunch is going
to use, but that rule does not solve the goal crunch is working on
then crunch will now error.
- if crunch fails to prove a goal it will now output a warning if
adding crunch_simps or crunch_wps would allow it to make more
progess.

lib: Add multi-crunch command 'crunches'.

It's just a parser tweak for crunch, and runs multiple crunch commands
with the same sections (wps, ignores, etc).

Also update the comments a little, and move them closer to the anchor of
command clicks (the @{command_keyword} antiquotation).

Removes all trailing whitespaces

Refactor of crunch.

Substantial adjustments to crunch. Main user changes are:
- 'lift' and 'unfold' mechanisms replaced by more general 'rule'.
- some more 'ignores' standardised.
- crunch has a more principled overall design:
+ discover crunch rule
* provided or by definition extraction
+ recurse according to rule
+ prove goal based on rule, recursive discoveries, standard tactic
* wp/simp adjustments tweak tactic

Added wp_del and simp_del arguments to crunch.

more Isabelle2015 update; AInvs up to (excluding) Syscall_AI

also includes some global replacements

ported lib/* theories to Isabelle2014-RC0

comment cleanup

release cleanup

Import release snapshot.