Initial draft of profile metadata format & CLI (#17)

* Initial draft of profile metadata format

* Remove records, add Clippy to Nix, fix Clippy error

* Work on profile definition

* BREAKING: Make global settings consistent with profile settings

* Add builder methods & format

* Integrate launching with profiles

* Add profile loading

* Launching via profile, API tweaks, and yak shaving

* Incremental update, committing everything due to personal system maintainance

* Prepare for review cycle

* Remove reminents of experimental work

* CLI: allow people to override the non-empty directory check

* Fix mistake in previous commit

* Handle trailing whitespace and newlines in prompts

* Revamp prompt to use dialoguer and support defaults

* Make requested changes

theseus/src/modpack/pack.rs

@@ -159,6 +159,7 @@ pub struct ModpackFile {
     pub downloads: HashSet<String>,
 }
 
+#[allow(clippy::derive_hash_xor_eq)]
 impl Hash for ModpackFile {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         if let Some(ref hashes) = self.hashes {