Added config reloading support.

Revision also includes:
* Added syntax checking on recoded/new console commands.
* Fixed sv_skyname handle being used when invalid.
* Fixed unhooking error on Weapon_Drop.
* Prefixed some API-style functions with 'stock' to stop compiler
warning.
* Separated downloads into its own file.

src/zombiereloaded.sp

@@ -31,6 +31,7 @@
 #include "zr/sayhooks"
 #include "zr/tools"
 #include "zr/models"
+#include "zr/downloads"
 #include "zr/overlays"
 #include "zr/playerclasses/playerclasses"
 #include "zr/weapons/weapons"
@@ -165,6 +166,7 @@ public OnConfigsExecuted()
     // Forward event to modules.
     ConfigLoad();
     ModelsLoad();
+    DownloadsLoad();
     WeaponsLoad();
     HitgroupsLoad();
     InfectLoad();