Bug 531950 - Make instances of IResource writable I also took an opportunity to do refactoring on the abstract provider, which then went onto other provider and finally ended up in core: * Remove redundant (not thrown) exceptions (recursively) * Extract system properties from Jena Provider to OSLCConstants and create getters in OSLC4JUtils for consistency * Refactor OSLC4JUtils to handle booleans better * Refactor RDF Provider to isolate OSLC Query specific logic Change-Id: Iebe663c2f47e68fe66d6c4f3dcd336a937077c34 Signed-off-by: Andrew Berezovskyi <andriib@kth.se>