test: Generate test cases from reference code

[gaocegege]

ref #10

There is a new config file needed when import a new reference code:

examples/
  reference/
    <function-name>/
      .property.yml
      <function-name>1/
        .test.yml
        <function-name>1.rpde
      <function-name>2/
      ...

test:
  reference: https://processing.org/reference/images/rect_0.png

Signed-off-by: Ce Gao ce.gao@outlook.com