Fix serve path failing to be absolute when given as a relative path

CHANGES.md

@@ -1,7 +1,7 @@
 # Rojo Change Log
 
 ## Current Master
-* *No changes*
+* Fixed `rojo serve` failing to correctly construct an absolute root path when passed as an argument
 
 ## 0.3.1
 * Improved error reporting when invalid JSON is found in a `rojo.json` project

src/bin.rs

@@ -85,7 +85,7 @@ fn main() {
             let sub_matches = sub_matches.unwrap();
 
             let project_path = match sub_matches.value_of("PROJECT") {
-                Some(v) => PathBuf::from(v),
+                Some(v) => canonicalish(PathBuf::from(v)),
                 None => std::env::current_dir().unwrap(),
             };