fixed example conf
ui: removed an erroneous warning message
ui: it is now possible to add custom links in tasks & taskrequests views

filling these global params with html will add links:
* webconsole.customactions.taskslist
* webconsole.customactions.requestslist
* webconsole.customactions.taskdetail
ui: no longer evaluate params values in params views
ui: removed a display warning message
ui: task triggers now display effects of 'requesttask' events

e.g. if a task "group.foo" defines "(onsuccess(requesttask bar))"
then the task "group.bar" will display this as a trigger:
"*onsuccess(group.foo)"
http tasks: set header using "setenv" rather than "param setheader"

Rationale: code is easier, behavior is consistent with local exec
setenv, seting default setenvs (TASKID, FQTN...) as HTTP headers
seems a rather good idea too, and Qt's QNetworkRequest::setRawHeader
do not support multi-valued headers therefore mono-valued setenv are
not the main restriction against multi-valued headers.
ui: let the schedule view be 100 tasks long, like other tasks views