[PATCH] YAML: Implement block scalar parsing

[Duncan P. N. Exon Smith]

> On 2015 May 6, at 17:57, Alex L <arphaman at gmail.com> wrote:
> 
> 
>   - You haven't added any new tests (although I see you've modified the
>     old ones).  Do the current tests really cover everything you've
>     changed here?  If not, please add some targeted ones. 
> 
> I did add a new test in the yaml parser unittest. I also did change the existing YAMLParser tests,
> but since they were never actually ran before I think that it's kind of equivalent to the
> addition of new tests.

Can you turn them on in a separate commit?