issue #78 - add copy context tree node function

[ghaliouss]

add a new function that copy the context tree node with all its childs.

[plynchnlm]

This looks useful, and thanks for contributing it. Do you have any ideas about what to do for fields which depend on linkIds, like enableWhen?

[ghaliouss]

This looks useful, and thanks for contributing it. Do you have any ideas about what to do for fields which depend on linkIds, like enableWhen?

Hello, the copy of a field that depend on linkId will depend on the same linkId of the original field.

only item's linkId and text properties are modified:

• the linkId is generated automaticaly as a random 12 digits number
• the text property is a concatination of the original text with 'Copy of ' string