Allow examples and test-suite to be built out of source tree

- Examples/Makefile.in rules use SRCDIR as the relative source directory

- ./config.status replicates Examples/ source directory tree in build
  directory, and copies each Makefile to build directory, prefixed with
  a header which sets SRCDIR to source directory

- Examples/test-suite/.../Makefile.in set SRCDIR from Autoconf-set srcdir

- Examples/test-suite/errors/Makefile.in needs to filter out source
  directory from SWIG error messages

- Lua: embedded interpreters are passed location of run-time test

- Python: copy run-time scripts to build directory because of 2to3
  conversion; import_packages example copies __init__.py from source
  directory; test-suite sets SCRIPTDIR to location of run-time tests

- Javascript: binding.gyp renamed to binding.gyp.in so that $srcdir
  can be substituted with SRCDIR; removed './' from require() statements
  so that NODE_PATH can be used to point Node.js to build directory

Examples/test-suite/javascript/node_template/binding.gyp.in

@@ -3,7 +3,7 @@
     {
       "target_name": "$testcase",
       "sources":[ "../$testcase_wrap.cxx" ],
-      "include_dirs": ["../.."],
+      "include_dirs": ["../$srcdir/.."],
       'defines': [
         'BUILDING_NODE_EXTENSION=1',
       ],