Structure the Harmony core to rely on a DAG for declaring & executing Scores

.gitignore

@@ -0,0 +1,19 @@
+### Rust ###
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+
+### rust-analyzer ###
+# Can be generated by other build systems other than cargo (ex: bazelbuild/rust_rules) 
+rust-project.json