Add `npm install bcrypt` to bundle README
Update docs for bcrypt dependency
Make docs `npm install` one line
Improve Deps stack traces

Change from `_assign(Deps.Computation.prototype, {foo: …})` style to `Computation.prototype.foo = …` style.

With the old style, Chrome had really bad names for stack frames, like `_assign.flush` instead of `Deps.flush`.
Merge branch 'devel' into blaze-refactor

Conflicts:
	packages/deps/deps.js

(Mysterious conflict makes no sense.  deps.js wasn't changed on devel...?)