Fix wrong page being displayed when entering/exiting Presentation mode with zoom set to 'page-fit'
Remove the unnecessary this.buf in CCITTFaxStream.
Remove some unnecessary local variables.
Merge pull request #4292 from Snuffleupagus/issue-4232

Fix wrong page being displayed when entering/exiting Presentation mode with zoom set to 'page-fit'
Merge pull request #4331 from nnethercote/cleanups

Minor clean-ups