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/guile/Makefile.in

@@ -6,10 +6,18 @@ EXTRA_TEST_CASES += guile_ext_test.externaltest
 
 LANGUAGE     = guile
 VARIANT      =
+SCRIPTDIR    = $(srcdir)
 SCRIPTSUFFIX = _runme.scm
+
 srcdir       = @srcdir@
 top_srcdir   = @top_srcdir@
 top_builddir = @top_builddir@
+ifeq (.,$(srcdir))
+SRCDIR =
+else
+SRCDIR = $(srcdir)/
+endif
+
 GUILE        = @GUILE@
 GUILE_RUNTIME=
 
@@ -51,8 +59,8 @@ INCLUDES    += -I$(top_srcdir)/$(EXAMPLES)/$(TEST_SUITE)/guile
 # Runs the testcase. A testcase is only run if
 # a file is found which has _runme.scm appended after the testcase name.
 run_testcase = \
-	if [ -f $(srcdir)/$(SCRIPTPREFIX)$*$(SCRIPTSUFFIX) ]; then \
-	  env GUILE_AUTO_COMPILE=0 LD_LIBRARY_PATH=.:$$LD_LIBRARY_PATH $(RUNTOOL) $(GUILE) -l $(srcdir)/$(SCRIPTPREFIX)$*$(SCRIPTSUFFIX); \
+	if [ -f $(SCRIPTDIR)/$(SCRIPTPREFIX)$*$(SCRIPTSUFFIX) ]; then \
+	  env GUILE_AUTO_COMPILE=0 LD_LIBRARY_PATH=.:$$LD_LIBRARY_PATH $(RUNTOOL) $(GUILE) -l $(SCRIPTDIR)/$(SCRIPTPREFIX)$*$(SCRIPTSUFFIX); \
 	fi
 
 # Clean