Customer mood changes upon CustomerInfo data

Customer texture and event mood change values are now read from
CustomerInfo.
Added & edited customer-related XML files

Added assets/customers.xml.
Edited days.xml: added customers="id1,id2,id3..." attribute, meaning
what customers can appear this day.
Changed customer goods data loading from XML

First, the customer ID is selected from current day customer list in
days.xml:

[days.xml]
<day index="0" duration="45" score="30,60,90" bags="0" goodsMaxID="2"
customers="grandma,woman">
and customer xml data is loaded from customers.xml using this customer
ID.

Customer xml data is, for example:

[customers.xml]
<customer id="grandma" mood="10" goodsMax="2">
<good id="0" counts="0112" />
<good id="1" counts="0012" />
<reaction event="customer_welcome" mood="15" />
<reaction event="customer_goodbye" mood="25" />
</customer>

where
<good>.counts: get 1 random char and treat it as int, meaning quantity
of that good.
<good>.<reaction>.mood means mood value change at the
<good>.<reaction>.event
<good>.id must be <= <day>.goodsMaxID

Added StrUtil static class, featuring:
randomPart(str: String, delim: String): String
returns random element from array produced by String.split(str, delim)
and
randomChar(str: String): String
that is obvious.

days.xml:
changed
<day>.goods: "minID-maxID" to
<day>.goodsMaxID: "maxID"
because minID is always 0.
Added: read reaction to events from customer XML
Merge remote-tracking branch 'origin/customer-mood-load-from-xml'