Formats HTML text (or, really, any text) similar to MessageFormat but with
the following features:
1) pass a hashtable of key/value pairs
keys MUST be String objects
values can be any object that has a toString() method
2) markup input text as follows:
Simple Insertion:
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{name} = insert 'name', via the 'toString' method
Formatted Insertion:
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{date:name,}
{decimal:name,}
specifiers are optional; locale-specific formatting used.