use logic name for urls.
add logic-name-url support to graphs.
add slug to logics

The slug is used as the param portion of a logic-url. It represents a
'cleaner' name where whitespace is replaced with underscores.
Additionally we also replace dots, stars and equality signs with
underscores.
create slugs for existing logics

This migration should contain a safeguard which should ensure that this
never fails (unless there is no logic class i guess...).
use slug to find logics in urls.
obey hound.
refactor freshen-fixtures task for readability.
extract hets-cmdline-options into config.
freshen fixtures only when necessary

'Necessary' is being determined by the modified timestamp of the
hets-binary (or wrapper-script) in relation to the xml-file which is to
be produced.
add freshen-task to default rake-task

And rely on this task when running travis, again.
fix default rake task

The default rake-task comes with spec and cucumber as dependencies. If
we provide more we just append to this list. So we'll clean the
prerequisites of those tasks beforehand.
replace * and = with spec. strings in logic-slug.
change fixture_file ontology-call to ontology_file.
Merge pull request #1112 from ontohub/fix_fixture_calls

change fixture_file ontology-call to ontology_file.
deactivate the hound-checker for multiline-lambda

As we want to use the 1.9 syntax (->(args)) for every lambda,
whether it is single-line or multi-line, we'll need to deactivate
the check, as it can't be configured.
set the label as display_name for obo-symbols.
return the query-hash, not its last element.
save entity/symbol only if it is not null.
GitRepo refactorings: more delegates, url -> path.
Delegate empty? method.