Added support for single-quoted Turtle string literals.

[alexdutton]

Fixes #325.

[coveralls]

Coverage increased (+0.0%) when pulling 9f7a1ed on ox-it:master into ec7bd49 on RDFLib:master.

[alexdutton]

Ah, sorry for not being clear. The N3 syntax doesn't allow single quotes around strings, so this will accept invalid N3. I'll get a test or two written, see about keeping the N3 parser as strict as it used to be, and update the pull request

[alexdutton]

So, the N3 parser is now no less strict, and there's a test in place to check that the Turtle parser accepts 'x' and '''x''' for strings, and that the N3 parser rejects it.

[coveralls]

Coverage increased (+0.04%) when pulling 59636b0 on ox-it:master into ec7bd49 on RDFLib:master.

[gromgull]

Great, thanks! (and apologies for the terrible ping)