Add meta tag with date for improved searching

The date currently appears in the generated file as follows:

<!-- Generated by javadoc (build 1.5.0-rc) on Wed Aug 11 07:21:52 PDT 2004 -->

Search engines cannot easily parse this. The information would
be much more readily available if it were in a meta tag.

This date specifies when the document was generated.
The date is trivial to provide, and the only practical one we can
provide. This should be close enough to the release to be of value.

The preferred format is:

   <meta name="date" content="YYYY-MM-DD">
such as:
   <meta name="date" content="2005-01-05">

NOTE: We understand that Google web search ignores meta tags,
but perhaps future versions would be smarter and would include
them for reputable websites or pages. They would not be
ignored by Sun's search engine (or possibly Google desktop search).

Ultraseek requires a W3C standard date tag and cannot, by default, read
custom tags such as DC and modified/create/etc date tags. The preferred
format is:

<meta name="date" content="YYYY-MM-DD">

###@###.### 2005-1-07 20:17:46 GMT
###@###.### 2005-05-06 16:56:42 GMT