Bug 890: Adding versatile Bitstream implementation

We already have several locations where bitstream operations are required and
partially implemented (JPEG decoder, media parsing, ..)
as well as endian related conversion (elf parser, ..).

Create a versatile Bitstream class allowing:
  - Utilize I/O operations on I/O streams, buffers and arrays
  - Consider MSBfirst / LSBfirst mode
  - Linear bit R/W operations
  - Bulk R/W operations w/ endian related type conversion
  - Allow mark/reset and switching streams and input/output mode
  - Optimized operations

Complete set of unit tests included, covering hopefully all cases.
Bug 980: Use Bitsream class for jogamp.common.os.elf.**