Boolean expression: parenthesis need to be surrounded by spaces

[djbe]

Refs #165.

This is either a bug in the implementation, or in the documentation. The docs say:
{% if (one or two) and three %}
But that won't work. It'll throw a "dangling token" error. What does work is:
{% if ( one or two ) and three %}

The reason is that the current implementation is just built on top of the components array received from the token parser, which separates by spaces. @ilyapuchka thoughts?

[ilyapuchka]

it shouldn't be like that, I need to look into that later