imports from properties (and LDAP configuration)

[Rod Widdowson]

I did a quick nature study.

- It is impossible to drive imports from a property file.  This is because
"Imports are resolved before bean (property-placeholder) creation".

- It is possible to drive imports from a system property (and you use the
${} syntax, not the %{} syntax).  Although I could see making this work for
a windows jetty install it doesn't feel right.

- There are, of course, other ways of driving this, but I'd defer to Daniel
for that and, as I said yesterday, I'd sooner do nothing in V3.0.0 rather
than hack up a solution in a hurry which we then become doomed to support
until 4.0

Rod