Add script to copy all demo, test and data files to build directory
  -- Make running this script a target in CMake
  -- Make all test targets dependent on this target.
  -- Now one does not need to run CMake to get changed test files
     copied to the build directory
Small fix in docstring generation
Speed up docstrng generation by a factor 50.
  -- Note to everyone
     re.compile is expensive...
Add option of generating SWIG files in arbitrary sub directory of dolfin source dir
Copy all swig files from source to build directory.
  -- This triggers SWIG also when nothing has happended. Need a way to fix this...
Autogenerate swig-interface if not already generated within the CMakeLists script
Fix problem of re-swigging after copying all swig files
Remove unused SWIG files
Remove debug statement
pdate README to new autogeneration of SWIG interface
Remove CMake files which are now autogenerated.
Add automatic run from within the main CMakeList.txt file of:

  ./cmake/scripts/generate-form-files
  ./cmake/scripts/generate-cmakefiles
  ./cmake/scripts/download-demo-data

if some specific files generated or downloaded from each one of
the scripts does not excist. One can still run the script manually.

We should consider generating and downloading these files to the build
 directory instead of the source directory.
Fix a directory reference in CMakeList file
Remove redundant call to generate-all in cmake.local
Add logic for calling copy-data if we have generated any data in
the present call to cmake.
Small tweeks to cmake files to make demo work.
Update ChangeLog with new cmake logics.

NOTE: To be able to run

     make demo

One need to run cmake twice.

 * First time CMakeLists.txt files are generated to demo directory
 * Second time the demo subdirectory is added
Make automatic generation of CMakeFiles, file downloading
and form files through cmake more robust.
Merge branch 'fix-issue-70'