wasm: Fix operation not supported on std::fs. Closes #115 (#166)

* Add new web-based std::fs replacement, localstoragefs:

https://github.com/iceiix/localstoragefs

* Add std_or_web to switch between std::fs (native) or localstoragefs (web)

* Update www readme for new missing glutin/winit links, opens issue #171

protocol/src/mod.rs

@@ -19,6 +19,7 @@ use aes::Aes128;
 use cfb8::Cfb8;
 use cfb8::stream_cipher::{NewStreamCipher, StreamCipher};
 use serde_json;
+use std_or_web::fs;
 #[cfg(not(target_arch = "wasm32"))]
 use reqwest;
 
@@ -1070,7 +1071,7 @@ impl Conn {
 
         if network_debug {
             debug!("about to parse id={:x}, dir={:?} state={:?}", id, dir, self.state);
-            std::fs::File::create("last-packet")?.write_all(buf.get_ref())?;
+            fs::File::create("last-packet")?.write_all(buf.get_ref())?;
         }
 
         let packet = packet::packet_by_id(self.protocol_version, self.state, dir, id, &mut buf)?;