Add current indent & text to all lines being pasted except if it duplicates

[jroachgit]

say you have a list:

- search and look for the likely forms:
	- <cursor here>
	

the data on the clipboard:

Capsule
concentrated extract
extract, concentrated
Flower

When pasting now:

- search and look for the likely forms:
	- Capsule
	  concentrated extract
	  extract, concentrated
	  Flower

Preferred paste outcome:

- search and look for the likely forms:
	- Capsule
	- concentrated extract
	- extract, concentrated
	- Flower

Further, if the clipboard data list was to look like this:

- Capsule
- concentrated extract
- extract, concentrated
- Flower

When pasted, it should not become:

- search and look for the likely forms:
	- - Capsule
	- - concentrated extract
	- - extract, concentrated
	- - Flower