Note pure/deterministic functions
Document asyncBind, lagBind, postLagBind

Affects #12
Remove allowMutations
Tweak wording on Angular
Tweak wording in tutorial
Update changes
Tweak `snap` description`
Document pre-commit hook
Document rxt.cast, rxt.cssify
Introduce rxt.cast in tutorial
Elaborate on Components
Document skipFirst
Document autoSub in changes/API
Release 0.0.5