Fix description of subprojects POMs file

by adding evaluationDependsOnChildren() on the root project. Thanks to
Peter Niederwieser for the hint.
Add OSGi Delcarative Service defintions

for smack-extensions, smack-experimental and smack-legacy. OSGi's
"Service Component Runtime" (SCR) will now take care of running the
initialization code of the particular Smack bundle.
Rework SmackInitializer interface definition.

Actually use FileUtils.getStreamForUrl() classloader argument.
Merge branch 'master' into osgi