Solidity Natspec multiline /** .. */ comments

- Natspec now works with `/** ... */` type of comments.
- Some work on better formatting of the extracted text, especially on the multiline comments case
- Adding CR ('\r') as whitespace in the scanner
- Some tests
This is a more simple check? The only disadvantage I can think of is that if Whitespace changes, then also this function needs to change, but that's not difficult to maintain. Which reminds me I should add '\r' in there.