Add capability to append a test step to a recorded script.

The capability to append a test step to a recorded script is now included and is documented here:

https://support.smartbear.com/loadninja/docs/scripts/editor.html

One needs to:

1. Click on the pencil icon of the event where one wishes to add a new step
2. Select Record new action
3. Select start recording new action: before (or after)
4. Click Record and Add