ws: Disconnect cleanly from session transport when web service goes away

Previously we would get handlers getting called after the CockpitWebService
instance had been destroyed.

Closes #1389
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: Don't complain if resource web response is already closed

Sometimes a web response closes for a failure such as a send.

Closes #1390
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
common: Don't include zero length blocks in template output

These just confuse all the other logic.

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
bridge: Substitute package name even for unknown packages

Substituting with a zero-length string is just plain unhelpful here.

Closes #1391
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
bridge: Don't complain about names of non-package directories

If a directory without a manifest.json file has an invalid name
we shouldn't be complaining about it with a warning.

Closes #1392
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
base: Work around unreadable monospace fonts in PatternFly

https://github.com/patternfly/patternfly/issues/39

Closes #1394
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
Add meta charset UTF-8 tags to all HTML files

The server can't really know what kind of content a given
HTML file will have, so the HTML files need to declare that
themselves.

Fixes #1368
Closes #1397
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>