Detect non-disjoint alternatives

[RunDevelopment]

To prevent exponential backtracking, the alternatives of a quantified group have to be disjoint (aside from the empty string and assertions).

For a RE /(A1|A2|...|An)*/, its alternatives have to disjoint such that:
∀ Aj: ( L(/(A1|...|Aj-1|Aj+1|An)*/) ∩ L(/Aj*/) ) \ {ε} = ∅ where L is a function which returns the language of the given RE and ε is the empty string.

This will be difficult to implement because we need to be able to construct an NFA from the RE and assertions don't make this any easier.

[RunDevelopment]

Test case: (?=[\t ]+[\S]{1,}|[\t ]+['"][\S]|[\t ]+$|$)

[RunDevelopment]

Resolved by #22.