Added option for ignoring not defined variables. Previously all not defined variables were replaced with empty string. If you want to alter this behaviour (keep not defined name) you can now use `ignore_missing` flag:
Globally:
*** Settings ***
Library TemplatedData ignore_missing=${True}
or locally:
${data} Get Templated Data ${template} ignore_missing=${True}
When set it will convert following template (with `${ROBOT_VARIABLE}` set to `10` and `${json-unit.any-string}` not defined at all):
{ "foo": "${ROBOT_VARIABLE}", "bar": "${json-unit.any-string}" }
to
{ "foo": "10", "bar": "${json-unit.any-string}" }
The downside of using `ignore_missing` is that any default values will be ignored.