Update upstream B/CB/S

--- work/Bukkit
Submodule work/Bukkit 6eac6d70..1ef8b9d9:
  > Add Player#openBook(ItemStack) method

--- work/CraftBukkit
Submodule work/CraftBukkit 17543ecf..649921e5:
  > Add Player#openBook(ItemStack) method
  > SPIGOT-2000: Picking up items to shield slot working inconsistently when inventory is full
  > SPIGOT-5037: Player.openMerchant does not show merchant level
  > SPIGOT-5038: Inventory.getHolder returns null for wandering traders

--- work/Spigot
Submodule work/Spigot baafee91..df0eb250:
  > SPIGOT-5043: Desync if world is changed in PlayerSpawnLocationEvent
  > Rebuild patches

Implementation developer note:
This patch adds a "pre-source" patch system for fixing malformed patches
from upstream directly. This seems to keep happening so it's best we
have some way to deal with them. This system brings those issues into
our domain rather than needing to wait for upstream to fix their
malformed files.

scripts/init.sh

@@ -16,6 +16,20 @@ if [ "x$patch" == "x" ]; then
     patch="$basedir/hctap.exe"
 fi
 
+# apply patches directly to the file tree
+# used to fix issues from upstream source repos
+cd $basedir
+prepatchesdir="$workdir/pre-source-patches"
+for file in $(ls $prepatchesdir)
+do
+    if [ $file == "README.md" ]; then
+        continue
+    fi
+
+    echo "--==-- Applying PRE-SOURCE patch: $file --==--"
+    $patch -p0 < "$prepatchesdir/$file"
+done
+
 echo "Applying CraftBukkit patches to NMS..."
 cd "$workdir/CraftBukkit"
 $gitcmd checkout -B patched HEAD >/dev/null 2>&1