Update Guild::ban to use BanOptions

Also update `Member::permissions` to the default channel change

src/model/guild/member.rs

@@ -274,8 +274,11 @@ impl Member {
     ///
     /// Returns a [`ModelError::GuildNotFound`] if the guild the member's in could not be
     /// found in the cache.
+    /// 
+    /// And/or returns [`ModelError::ItemMissing`] if the "default channel" of the guild is not found.
     ///
     /// [`ModelError::GuildNotFound`]: enum.ModelError.html#variant.GuildNotFound
+    /// [`ModelError::ItemMissing`]: enum.ModelError.html#variant.ItemMissing
     #[cfg(feature = "cache")]
     pub fn permissions(&self) -> Result<Permissions> {
         let guild = match self.guild_id.find() {
@@ -285,8 +288,13 @@ impl Member {
 
         let guild = guild.read().unwrap();
 
+        let default_channel = match guild.default_channel() {
+            Some(dc) => dc,
+            None => return Err(From::from(ModelError::ItemMissing)),
+        };
+
         Ok(guild.permissions_for(
-            ChannelId(guild.id.0),
+            default_channel.id,
             self.user.read().unwrap().id,
         ))
     }

src/model/guild/mod.rs

@@ -207,13 +207,7 @@ impl Guild {
     /// [`Guild::ban`]: struct.Guild.html#method.ban
     /// [`User`]: struct.User.html
     /// [Ban Members]: permissions/constant.BAN_MEMBERS.html
-    pub fn ban<U: Into<UserId>>(&self, user: U, delete_message_days: u8) -> Result<()> {
-        if delete_message_days > 7 {
-            return Err(Error::Model(
-                ModelError::DeleteMessageDaysAmount(delete_message_days),
-            ));
-        }
-
+    pub fn ban<U: Into<UserId>, BO: BanOptions>(&self, user: U, options: BO) -> Result<()> {        
         #[cfg(feature = "cache")]
         {
             let req = permissions::BAN_MEMBERS;
@@ -223,7 +217,7 @@ impl Guild {
             }
         }
 
-        self.id.ban(user, delete_message_days)
+        self.id.ban(user, options)
     }
 
     /// Retrieves a list of [`Ban`]s for the guild.