The idea is to avoid to have the pasted editor hidding the copied one:
the user could think that nothing happened.
So the top-left corner of the pasted one is moved to the bottom-right corner of the copied one.
This patch fixes an issue when pasting: an exception was thrown when pasting.
And while writing the test and comparing the paths in the svg, I found a difference
which is fixed thanks to call to the right constructor (to take into account the inheritance)
in inkdraw.js
