Remove deprecated functionality.

In looking through IO.chpl for file functionality, I noticed some methods
which inform the user that they are no longer supported.  Since this message
was added in 2011, it seems reasonable to remove it.
Remove a method that has been commented out since 2011
With the exception of the mandelbrot test, all test files changed for this
commit had commented out usage of FileAccessMode, which was needed in the
deprecated method to open a file.  The mandelbrot test had created an entirely
separate module to store the old version, but since we have deprecated the
feature, this seemed no longer necessary to maintain.
Merge pull request #164 from lydia-duncan/removeDeprecatedFileOps

Remove deprecated file ops and references to them [reviewed by mppf]

In looking through IO.chpl for file functionality, I noticed some functions
which inform the user that they are no longer supported or which were
commented out and trivial. Since the code had been in this state since
it was added in 2011, it seems reasonable to remove the functions in question.
With the exception of the mandelbrot test, all test files changed for this
commit had commented out usage of FileAccessMode, which was needed in the
deprecated method to open a file.  The mandelbrot test had created an entirely
separate module to store the old version, but since we have deprecated the
feature, this seemed no longer necessary to maintain.