Use the _availablePackages completion function instead of _sai.

This follows the sjoubert function rename.
Addition of a function illustrating a elnode use case.

It shows my current buffer over http.
Addition of a precision about what to do with some entries
Change the yesterday report in a yesterworkday.

This new report shows what was done on friday if today is monday.
Get rid of the konix/org-agenda-tag-filter-preset option.

I often want to filter agenda's entries with a or pattern, showing
for instances tasks that may be done at home (@home) or at a
computer.  To do so, the auto-exclude function seems to be the way
to go.

The feature of konix/org-agenda-tag-filter-preset is then replaced
by a more general konix/org-agenda-tag-filter-contexts feature
that remove any context (tag beginning with @) not in
konix/org-agenda-tag-filter-contexts.

The feature behaves like konix/org-agenda-tag-filter-preset in the sense that
the value of the feature is taken into account when any agenda is created.

To do so, org-agenda is adviced to perform the filter automatically like if /
Ret was pressed at the beginning of each agenda.

The hotkeys are updated to follow the change.
Start trac-wiki in abbrev mode
Fix the link regexp to take into account the ends of lines.
Update the generated accel_map to represent the new name of the mirage application.
Do not follow the focus of the mouse in terminator.
Try to launch the per_site_user_agent.sh synchronously.

This is done to avoid the request to be sent to the server before
the user agent has been changed.

Actually, the per_site_user_agent.sh changes the user agent in a
asynchronous way. Even if it is launched at the earliest time, the
request with uzbl user agent is made before it has been changed by
the script.

I am not sure whether doing a sync_spawn will insure the script
will be terminated before the page is requested and then the user
agent will be correctly set, but it is worth trying.