OffHeapMemoryBuffer leaks 1 byte at every allocation

Discussed here : http://goo.gl/FCkix

• OffHeapMemoryBuffer shouldn't throw a NPE when store function don't
  find "goodOne" pointer. Should return null instead to allow
  MemoryManagerService to try another buffer if available. See
  testAllocateMultipleBuffers function in the attached class :
  initializing 4 buffers of 4 bytes, I should be able to store 4 objects
  of 4 bytes each.

• OffHeapMemoryBuffer leaks one byte at every allocation. This is
  because the pointer is 0 indexed, so a pointer starting at 0 and
  ending at 3 is 4 bytes, not 3. See testByteLeaking function :
  initializing 1 buffer of 40 bytes, I should be able to store 10
  objects of 4 bytes each. I would also suggest to have a function
  Pointer.getSize() { return end - start + 1; }

• OffHeapMemoryBuffer.firstMatch should compare pointer capacity to
  find a match and not only the ending offset. Doing the correct
  comparison will avoid a costly BufferOverflowException.

• OffHeapMemoryBuffer don't report the correct used size (once the
  leak is removed) when freeing a pointer. See
  testReportCorrectUsedMemory : allocating the whole buffer, freeing a
  pointer, reallocating this pointer. The resulting usage should again
  be the full buffer.