break sp-api dependency cycle (#4352)

* move benches into tests, ignore non-passing doctests

* Rename sr-api folder

* Move test-primitives to primitives, use that for sp-api doctests

substrate/primitives/api/proc-macro/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "sp-api-proc-macro"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = "1.0.2"
+syn = { version = "1.0.8", features = ["full", "fold", "extra-traits", "visit"] }
+proc-macro2 = "1.0.6"
+blake2-rfc = "0.2.18"
+proc-macro-crate = "0.1.4"
+
+# Required for the doc tests
+[features]
+default = [ "std" ]
+std = []