v0.2.0: Add support for :private-members: option

Added

• Viewcode functionality which allows for listing the source C files and
  providing links between the documentation and the C source listings.
• :private-members: and :no-private-members: option for the autocmodule
  directive. This option set allows for controlling the documentation of
  constructs based on what is visible outside of the module. For header
  files this means everything will still be documented. For standard source
  files only non static functions and non static variables will be auto
  documented if the :private-members: is not specified, or the
  :no-private-members: is specified.

Fixes

• Anonymous enumerations which were contained in a typedef were being documented twice.
  Once as the typedef and once as anonymous. Now they are only documnted as
  part of the typedef.