Plug-in Project build path 

1. Added bundle org.eclipse.pde.ds.lib with annotations.jar containing
org.osgi.service.component.annotations package (with sources) so that
users can reference the annotations at build time only instead of using
Import-Package.

2. Contributed annotations.jar into bundle plug-in projects' transient
build path (based on preferences) so that DS annotations are immediately
available to users without additional configuration.

3. Added problem marker (with resolutions) to remind users to include
annotations.jar in their projects' permanent build path if only the
transient contributed entry is detected.

Change-Id: I2dd09312657a0bc9a605f75e474c43d86ce1ab99
Signed-off-by: Peter Nehrer <pnehrer@eclipticalsoftware.com>