Hacking on grammar! proc macro

- Generated functions take parser state as input
- Start of code generation
- WIP modeling of sequences

Cargo.lock

@@ -131,6 +131,7 @@ checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
 name = "peg_macro"
 version = "0.1.0"
 dependencies = [
+ "proc-macro2",
  "quote",
  "syn",
 ]
@@ -168,9 +169,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.94"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a31971752e70b8b2686d7e46ec17fb38dad4051d94024c88df49b667caea9c84"
+checksum = "02b3e5e68a3a1a02aad3ec490a98007cbc13c37cbe84a3cd7b8e406d76e7f778"
 dependencies = [
  "unicode-ident",
 ]