Trailing whitespace significant when calling :filter

[enosis]

In a Haml document, calling a filter with trailing whitespace (":preserve ") is taken as significant, resulting in unknown filter. Code also (initially) admits 'blank' filter name.

Perhaps it should be alphanum+_? Candidate repair at commit:
http://github.com/enosis/text-haml/commit/34ed02bf393f6c3f38ca55f40a8a03b969eda2e0

[vti]

Thanks, fixed and pushed :)