Isabelle2018: new "op x" syntax; now is "(x)"

(result of "isabelle update_op -m <dir>")

Isabelle2018: new comment syntax

(result of "isabelle update_comments <dirs>")

globally use session-qualified imports; add Lib session

Session-qualified imports will be required for Isabelle2018 and help clarify
the structure of sessions in the build tree.

This commit mainly adds a new set of sessions for lib/, including a Lib
session that includes most theories in lib/ and a few separate sessions for
parts that have dependencies beyond CParser or are separate AFP sessions.
The group "lib" collects all lib/ sessions.

As a consequence, other theories should use lib/ theories by session name,
not by path, which in turns means spec and proof sessions should also refer
to each other by session name, not path, to avoid duplicate theory errors in
theory merges later.

Removes all trailing whitespaces

Isabelle2016-1: syntax: use semantic markup instead of "header"

trivial: remove some redundant uses of split_if rule

terminology in comments: async ep -> notifications

add arch_tcb object to C, rename aep -> ntfn

bisim: Isabelle 2014 changes.

integrate separation kernel config proofs

Hooked up into build system and regression test; added READMEs

github import of static cap config proofs