#233 HTTP URL scanning support

[Jeremy Boynes]

Support has been added for scanning HTTP locations
using the WebDAV protocol. This allows locations to be
scanned when the server has been netbooted from a web
server in the same manner as local directories are
scanned. This allows JBoss to be booted from an
unmodified configuration located on a WebDAV capable
server such as Tomcat 4.1.X, Apache 2.0 with mod_dav or
even Microsoft IIS. Alternatively, a trival DAV server
is supplied in docs/examples/netboot that allows JBoss
to be booted from any J2EE WebContainer such as JBossWeb.

DAV scanning is supported for the SARDeployer
<classpath> element and for the URLDeploymentScanner
<urls> element. The latter requires locations to be
specified in accordance with RFC2518 - basically URLs
will be scanned if they end with a '/' character and
deployed if they do not. See the standard
conf/jboss-service.xml for examples.

With this change URLDeploymentScanner is now able to
provide the functionality of URLDirectoryScanner and
HttpURLDeploymentScanner and these mbeans should no
longer be used.

A current limitation is that locations to be scanned
via HTTP/DAV must not contain unpacked archives
(especially SAR or WAR archives). This limitation may
be removed in the future.

Also WAR archives should contain in their lib or
classes directories all classes needed to compile JSP
pages. Strictly, the javac compiler invoked during JSP
compilation uses a classpath derived from ClassLoaders
referencing the local filesystem; as a result
dependencies on classes loaded over the network may
result in "cannot resolve symbol" errors during JSP
compilation.