Template variable

fix date to load by default does not always work

add link to changelog in email notification if update is a stable update

Fixed font error while generating pfd report

Changed the Email report to look more consistent with the piwik UI.

Refs #6968, add --w3c-fields option to log importer so log files in W3C extended log file format can be imported from stdin w/o a '#Fields:' line being present.

Remove dependency on Piwik DI in generate:travis-yml command (for travis builds against older piwik versions).

Fix curl timeout not set completely: this could result in Piwik hang indefinitely on an HTTP request

More particularly, this resulted in the installation hanging at the second step (system check) when using PHP's built-in webserver.

Fixes #6968, support parsing W3C extended log files from stdin in log importer by refactor W3cExtendedFormat class so it does not seek when creating the regex used when parsing logs. Also make sure to initialize the format class when --log-format-name=w3c_extended is used. Includes fixes to python tests.

During development we still want to use a cache to cache items that are requested multiple times during one request. For example Marketplace API calls. The marketplace page in dev mode does now load in about 4 seconds instead of 30 seconds. Also plugin components etc. will now longer loaded multiple times.