A better Analysis tutorial in the README.

Complete Analysis redesign.

• The Analysis class now has two type parameters: a domain and a
  language, and no longer has an associated type family
• The analysis no longer has any knowledge of the e-graph:
  • makeA now has type l domain -> domain, that is, to make a domain
    of a new node we only have to take into consideration the data of
    the sub-nodes of the new node.
  • joinA is unchanged.
  • modifyA now has type EClass domain lang -> (EClass domain lang, [Fix lang]). It takes an e-class and optionally modifies it,
    possibly by adding nodes to it. The return value is the modified
    e-class, and a list of expressions from the language to add to the
    e-class.
• We can now compose analysis and create language-polymorphic analysis. Such
  two examples are the analysis with domain () which regardless of the
  language simply ignores the domain: instance Analysis () l; and the
  second example is the product of analysis, which composes two separate
  analysis into one: instance (Analysis a l, Analysis b l) => Analysis (a,b) l.
• An EGraph now also has two type parameters instead of one (the latter is
  the language is the former the domain of the analysis).

Allow customization of Schedulers through parameters (by accepting a scheduler
rather than a proxy for it)