API doc: fix end slashes and examples

Add end slashed to all urls.
Match examples with default-fixture.
Improve test strategy when creating users

Plus the tests did not work against PostgreSQL because of a mistake: the id of the newly created user was hard
coded as 1, instead of being read with user.id.
Merge pull request #243 from nimiq/api

Help page and ending slashed fixed
bugfixes to mbox importer
Merge branch 'api'
datadump update
updated selenium tests, final tweaks to multi tag filtering
changes from Marc
Merge branch 'master' of https://github.com/Bioconductor/biostar-central
Merge branch 'master' of https://github.com/ialbert/biostar-central into istvan
Merge branch 'istvan'