Fixed JERSEY-1956.

- InMemoryContainer was ignoring headers for requests with no entity.

Change-Id: Ia9dba5f055b34c630e6b4408a661b4c568caa566
Signed-off-by: Marek Potociar <marek.potociar@oracle.com>
Fixed JERSEY-1990.

- MBR.isReadable and MBW.isWriteable are wrapped in try/catch to deal with potential exceptions thrown from these methods.
- Added reproducer test.
- Refactored MessageBodyFactory (renames, switched to new concurrency maps, removed redundant fields, all fields made final.

Change-Id: Ibea93e091dd40e8f6e98d5057f8054867d32d4ac
Signed-off-by: Marek Potociar <marek.potociar@oracle.com>
Merge "Fixed JERSEY-1956."