Replace spaces with "%20" in "urlPrefix", before markdon processing.
The spaces were causing blackfriday (markdown processor) to behave
strange. This fixes#2545.
Make user search function look in username (lower_name), full name
(full_name) and primary email (email). This will benefit searching after
user in "explore", admin panel and when adding new collaborators.
Set the description meta tag correctly when there is no repo
description. Also use the ability to trim trailing whitespaces,
to make the template cleaner.