Fold runtime/ crate into this source tree

While I like the idea of having a runtime completely decoupled from the
syntax and compiler, I don't think this is that big of a project for
that to be necessary or even useful yet.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

Cargo.toml

@@ -17,10 +17,13 @@ lrpar = "0.9"
 lrlex = "0.9"
 structopt = "0.3"
 snafu = "0.6.6"
+maplit = "1.0.2"
+once_cell = "1.4.1"
 
 #lazy_static = "1.4.0"
 #regex = "1.3.7"
 #derivative = "2.1.1"
 
-[dependencies.runtime]
-path = "runtime"
+[dependencies.shredder]
+git = "https://github.com/Others/shredder"
+features = ["nightly-features"]