ENH: Update Slicer driver dashboard script to display variables.

This will facilitate understanding of the build context.

Here is an example of output:

$ ctest -S slicer_experimental.cmake -VV

• Extra verbosity turned on
  Reading Script: /home/jcfr/Projects/sandbox/slicer_experimental.cmake
  -- Setting 'MIDAS_PACKAGE_URL' variable with default value 'http://slicer.kitware.com/midas3'
  -- Setting 'MIDAS_PACKAGE_EMAIL' variable with environment variable value 'OBFUSCATED'
  -- Setting 'MIDAS_PACKAGE_API_KEY' variable with environment variable value 'OBFUSCATED'
  -- Setting 'run_ctest_with_disable_clean' variable with default value 'FALSE'
  -- Setting 'run_ctest_with_configure' variable with default value 'TRUE'
  -- Setting 'run_ctest_with_coverage' variable with default value 'TRUE'
  -- Setting 'run_ctest_with_memcheck' variable with default value 'TRUE'
  -- Setting 'run_ctest_with_packages' variable with default value 'TRUE'
  -- Setting 'run_ctest_with_upload' variable with default value 'TRUE'
  -- Setting 'run_ctest_with_notes' variable with default value 'TRUE'
  -- CTEST_SITE ........................: cerrotorre.kitware
  -- CTEST_BUILD_NAME ..................: Linux-g++5.2.1-64bits-QT4.8.7-PythonQt-With-Tcl-NoCLI-Release
  -- SCRIPT_MODE .......................: experimental
  -- CTEST_BUILD_CONFIGURATION .........: Release
  -- WITH_MEMCHECK .....................: FALSE
  -- WITH_COVERAGE .....................: FALSE
  -- WITH_DOCUMENTATION ................: FALSE
  -- ADDITIONAL_CMAKECACHE_OPTION ......:

-- CTEST_NOTES_FILES .................: /home/jcfr/Projects/sandbox/slicer_experimental.cmake
-- CTEST_DASHBOARD_ROOT ..............: /home/jcfr/Projects/
-- CTEST_CMAKE_GENERATOR .............: Unix Makefiles
-- CTEST_TEST_TIMEOUT ................: 500
-- CTEST_BUILD_FLAGS .................: -j8
-- TEST_TO_EXCLUDE_REGEX .............:
-- CTEST_PROJECT_NAME ................: Slicer4
-- CTEST_SOURCE_DIRECTORY ............: /home/jcfr/Projects//Slicer
-- CTEST_BINARY_DIRECTORY ............: /home/jcfr/Projects//Slicer-Release
-- CTEST_COVERAGE_COMMAND ............: /usr/bin/gcov
-- CTEST_MEMORYCHECK_COMMAND .........: /usr/bin/valgrind
-- CTEST_SVN_COMMAND .................: /usr/bin/svn
-- CTEST_GIT_COMMAND .................: /usr/bin/git
-- QT_QMAKE_EXECUTABLE ...............: /home/jcfr/Support/qt-everywhere-opensource-build-4.8.7/bin/qmake
-- CTEST_CONFIGURATION_TYPE ..........: Release
-- CTEST_LOG_FILE ....................: NOT DEFINED
-- CTEST_NOTES_FILES .................: /home/jcfr/Projects/sandbox/slicer_experimental.cmake
-- CTEST_PARALLEL_LEVEL ..............: 8
-- MIDAS_PACKAGE_URL .................: http://slicer.kitware.com/midas3
-- run_ctest_submit ..................: 1
-- run_ctest_with_disable_clean ......: FALSE
-- run_ctest_with_update .............: 0
-- run_ctest_with_configure ..........: TRUE
-- run_ctest_with_build ..............: 0
-- run_ctest_with_test ...............: 0
-- run_ctest_with_coverage ...........: TRUE
-- run_ctest_with_memcheck ...........: TRUE
-- run_ctest_with_packages ...........: TRUE
-- run_ctest_with_upload .............: TRUE
-- run_ctest_with_notes ..............: TRUE
-- SVN_REPOSITORY ....................: http://svn.slicer.org/Slicer4
-- SVN_BRANCH ........................: trunk
-- SVN_REVISION ......................:
-- SVN_URL ...........................: http://svn.slicer.org/Slicer4/trunk
-- empty_binary_directory ............: FALSE
-- force_build .......................: TRUE
-- model .............................: Experimental
-- track .............................: Experimental-Packages
-- CTEST_USE_LAUNCHERS ...............: 1
[...]

From: Jean-Christophe Fillion-Robin <jchris.fillionr@kitware.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24985 3bd1e089-480b-0410-8dfb-8563597acbee