Update with changes from graphql 0.12 and 0.13

[danez]

I already started going through the commits of graphql and picking relevant changes.

• [WIP][0.13] Separate multiple inherited interfaces with & #237
• [0.12][WIP] Block Strings #238
• [0.12] Fix how TypeInfo handles inline fragments without type #239
• [0.12] Uniform parsing of queries with short-hand syntax with regular queries #240
• [0.12][WIP] Small upstream updates #241
• [0.12] Descriptions as strings #242

If you prefer I can also put the changes all in one branch.

I hope this is okay, but we would like to use some of the new features in my company and after I started I noticed it is fun todo, so I decided to go through all commits. :D

[vladar]

Hey @danez this is cool! I will be able to review/merge them somewhere at the beginning of the next week. Feel free to port as much as you want %) Thanks for those PRs!

[vladar]

Finally merged %)