new xml Element <month>

Add a new xml Element <month> for run times.
<month> is a repeatable child Element of <run_time>
<month> limits the runtimes of it's children to the month which is configured with the month attribute.
Valid values for the attribute month are: 1,2,3,4,5,6,7,8,9,10,11,12,January,February,March,April,May,June,July,August,September,October,November,December

<month> can have the following children:
<period>
<weekdays>
<monthday>
<ultimos>

Examples:
In January, run every day at 10:10
<run_time>
<month month="1">
<period single_start="10:10" />
</month>
</run_time>

In February, run every Monday and Tuesday at 10:10
<run_time>
<month month="2">
<monthdays>
<weekday day="monday">
<period single_start="10:10" />
</weekday>
<weekday day="tuesday">
<period single_start="10:10" />
</weekday>
</monthdays>
</month>
</run_time>

Run on the first Monday of February
<run_time>
<month month="2">
<monthdays>
<weekday day="monday" which="1">
<period single_start="10:10" />
</weekday>
</monthdays>
</month>
</run_time>

Run once every year on the 17th of November at 08:10
<run_time>
<month month="11">
<monthdays>
<day day="17">
<period single_start="08:10" />
</day>
</monthdays>
</month>
</run_time>