Fix parsing token components with parenthesis without spaces

[ilyapuchka]

Resolves #253

[djbe]

Just being pedantic here, but we want to make sure we cover all cases:

Does this handle a (badly written) expression like:

(one and two )or three

[AliSoftware]

Good point. If you're asking the question @djbe that means we need a test to cover it 😉

[ilyapuchka]

it won't handle two )or though it should, good catch

[djbe]

We may want to keep an eye on performance with those multiple repeated hasPrefix/hasSuffix tests (don't want to end up having to do another #226).

Don't forget the changelog entry! 😄

[djbe]

Please avoid force unwraps, especially in Sources.

You could:

• use word[0]
• unroll the if test into a separate one
• use prefix(1)
• ...