Made the syllabification context the scope of rules.

In order to maintain lambda semantics (being able to use return in the rule) and not have arity complaints each rule is defined on the context while it is evaluated. I have no idea what performance implications this has.
Updated README to reflect changes.
Merge pull request #16 from gwagener/context_as_rule_scope

Made the syllabification context the scope of rules
Merge branch 'master' into voicing