Fix bug in prioritization (#63)

The stream buffered data counter was never decremented.

src/frame/mod.rs

@@ -54,6 +54,7 @@ pub use self::window_update::WindowUpdate;
 // Re-export some constants
 pub use self::settings::{
     DEFAULT_SETTINGS_HEADER_TABLE_SIZE,
+    DEFAULT_INITIAL_WINDOW_SIZE,
     DEFAULT_MAX_FRAME_SIZE,
     MAX_INITIAL_WINDOW_SIZE,
     MAX_MAX_FRAME_SIZE,

src/frame/ping.rs

@@ -12,6 +12,7 @@ pub struct Ping {
 }
 
 impl Ping {
+    #[cfg(feature = "unstable")]
     pub fn new() -> Ping {
         Ping {
             ack: false,

src/frame/settings.rs

@@ -36,6 +36,9 @@ const ALL: u8 = ACK;
 /// The default value of SETTINGS_HEADER_TABLE_SIZE
 pub const DEFAULT_SETTINGS_HEADER_TABLE_SIZE: usize = 4_096;
 
+/// The default value of SETTINGS_INITIAL_WINDOW_SIZE
+pub const DEFAULT_INITIAL_WINDOW_SIZE: u32 = 65_535;
+
 /// The default value of MAX_FRAME_SIZE
 pub const DEFAULT_MAX_FRAME_SIZE: FrameSize = 16_384;