Remove redundant lemma.

Proof got much bigger for some reason, which doesn't make much
sense. Need to investigate.
Make decoding function depend on memory.
Restate some lemmas to use only decoding function.
Use is_true in refinement_common.
Flip argument order to help unification.
Use and4 in cache_correct.
Adapt existT injectivity lemma to eqType.
Start splitting SERVICE from other opcodes.
Remove intermediate decoding step, inversion lemma
Fix more rule definitions.
Bring back proof of analyze_cache.
Include monotonicity condition in decoding.
Tweak statement of analyze_cache.
Parameterize encodable class by tag kind.
Some fixes.