Add ability to specify address in default.project.json (#507)

* Allow for setting the default port in project json

set as
```json
"serveAddress": "0.0.0.0"
```

* Update CHANGELOG.md

* cargo fmt

Co-authored-by: Lucien Greathouse <me@lpghatguy.com>

src/project.rs

@@ -1,6 +1,7 @@
 use std::{
     collections::{BTreeMap, HashMap, HashSet},
     fs, io,
+    net::IpAddr,
     path::{Path, PathBuf},
 };
 
@@ -67,6 +68,11 @@ pub struct Project {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub game_id: Option<u64>,
 
+    /// If specified, this address will be used in place of the default address
+    /// As long as --address is unprovided.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub serve_address: Option<IpAddr>,
+
     /// A list of globs, relative to the folder the project file is in, that
     /// match files that should be excluded if Rojo encounters them.
     #[serde(default, skip_serializing_if = "Vec::is_empty")]