add schedules/schedule elemens to config xml

Add a new <schedules> element as child of <config>
<schedules> element can have <schedule> children:
<schedule> element has a name attribute and the same children as a <run_time> element, e.g.:

<schedules>
<schedule name="in_the_morning" title="Morning Schedule">
<weekdays>
<day day="1 2 3 4 5">
<period single_start="07:30"/>
</day>
</weekdays>
</schedule>
<schedule name="in_the_evening">
...
</schedule>
</schedules>

Schedules can be referenced in run times:
<job name="hello">
<process file="hello.sh"/>
<run_time schedule="in_the_morning"/>
</job>

Enhancements to XML Answers:
/spooler/answer/job, /spooler/answer/jobs/job, /spooler/answer/order and all other nested order elements get a new attribute active_schedule, which points to the schedule currently used by this job/order (which may be a replacement schedule). If the job/order is not using a schedule, the attribute is not created.

<show_state what="schedules"/> returns a listing of all schedules and the jobs/orders which are using this schedule. Replacement schedules are also returned. Schedules which are currently active (either the standard schedule which is currently not replaced, or a replacement schedule which is currently replacing another schedule) get an attribute active="yes", all others have active="no", e.g.:

<spooler>
<answer>
<state>
<schedules>
<schedule path="/samples/in_the_morning" name="in_the_morning" title="Morning Schedule"
active="yes">
<weekdays>
<day day="1 2 3 4 5">
<period single_start="07:30"/>
</day>
</weekdays>
<file_based .../>
<schedule.users>
<schedule.user job="/samples/jobA11"/>
<schedule.user job_chain="/samples/chain_A"
order="/samples/order_A"/>
</schedule.users>
</schedule>
<schedule path="/samples/in_the_morning_replacement_1"
name="in_the_morning_replacement_1" substitute="/samples/in_the_morning"
valid_from="2008-04-12 00:00:00" valid_to="2008-04-13 23:59:00" active="no">
<weekdays>
<day day="1 2 3 4 5">
<period single_start="09:30"/>
<period single_start="15:30"/>
</day>
</weekdays>
</schedule>
</schedules>
</state>
</answer>
</spooler>