Rewrite Project, remove SourceProject (#274)

* Rewrite project file to have relative paths and drop SourceProject

* Redo project error types

* Tidy up and document Project type

* Strip out init command

src/common_setup.rs

@@ -6,7 +6,7 @@ use std::path::Path;
 use rbx_dom_weak::RbxInstanceProperties;
 
 use crate::{
-    project::{Project, ProjectLoadError},
+    project::Project,
     snapshot::{
         apply_patch_set, compute_patch_set, InstanceContext, InstancePropertiesWithMeta, RojoTree,
     },
@@ -19,11 +19,7 @@ pub fn start<F: VfsFetcher>(
     vfs: &Vfs<F>,
 ) -> (Option<Project>, RojoTree) {
     log::trace!("Loading project file from {}", fuzzy_project_path.display());
-    let maybe_project = match Project::load_fuzzy(fuzzy_project_path) {
-        Ok(project) => Some(project),
-        Err(ProjectLoadError::NotFound) => None,
-        Err(other) => panic!("{}", other), // TODO: return error upward
-    };
+    let maybe_project = Project::load_fuzzy(fuzzy_project_path).expect("TODO: Project load failed");
 
     log::trace!("Constructing initial tree");
     let mut tree = RojoTree::new(InstancePropertiesWithMeta {
@@ -37,23 +33,13 @@ pub fn start<F: VfsFetcher>(
 
     let root_id = tree.get_root_id();
 
-    log::trace!("Constructing snapshot context");
-    let snapshot_context = InstanceContext::default();
-    if let Some(project) = &maybe_project {
-        // If the project file defines no plugins, then there's no need to
-        // initialize the snapshot plugin context.
-        if !project.plugins.is_empty() {
-            // TODO: Initialize plugins in instance context
-        }
-    }
-
     log::trace!("Reading project root");
     let entry = vfs
         .get(fuzzy_project_path)
         .expect("could not get project path");
 
     log::trace!("Generating snapshot of instances from VFS");
-    let snapshot = snapshot_from_vfs(&snapshot_context, vfs, &entry)
+    let snapshot = snapshot_from_vfs(&InstanceContext::default(), vfs, &entry)
         .expect("snapshot failed")
         .expect("snapshot did not return an instance");