HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Fix some issues with the threading in the python example, and use #option
rather than command line flags to pick up required library.

This example should now work 'out of the box' on a standard linux install.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Improve the Java example so that it does not need complex command line options
to build, and can work 'out of the box' on a standard linux install.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Add a second Python example, and fix some code in the first example that was
not freeing Python objects (changed the code when debugging and forgot to
change back).

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling JavaScript from ECL

Add an example using the V8 Javascript engine from ECL

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling Python, Java, Javascript from ECL

Corrected to use rtlMalloc rather than new char.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling Python, Java, Javascript from ECL

Add a JavaScript example that uses Mozilla SpiderMonkey.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Various typos in comments

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #3832 from richardkchapman/java-python-examples

HPCC-8541 - Add examples illustrating calling Python and Java from ECL

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>