Fix the grammar of the offtopic template.
Merge pull request #268 from dpryan79/master

Fix the grammar of the off-topic template.
Fix #270

Multi tag filtering has been removed: this commit removes its relative tests.
Merge pull request #274 from nimiq/fix#270

Fix #270
Merge branch 'master' of https://github.com/ialbert/biostar-central into istvan