Vessels: Smaller/improved textures, remove duplicated 'inv' textures

Removed unnecessary inventory textures
The drinking glass inventory texture now differs from
the node texture to be more clearly a drinking glass
Smaller textures to reduce size as nodes

mods/vessels/README.txt

@@ -43,3 +43,8 @@ Authors of media files
 Unless specifically noted,
 Copyright (C) 2012 Vanessa Ezekowitz
 
+The following textures were modified by Thomas-S (License is CC0):
+    vessels_drinking_glass.png
+    vessels_drinking_glass_inv.png (Paramat helped to improve this texture)
+    vessels_glass_bottle.png
+    vessels_steel_bottle.png

mods/vessels/init.lua

@@ -70,14 +70,14 @@ minetest.register_node("vessels:glass_bottle", {
 	description = "Glass Bottle (empty)",
 	drawtype = "plantlike",
 	tiles = {"vessels_glass_bottle.png"},
-	inventory_image = "vessels_glass_bottle_inv.png",
+	inventory_image = "vessels_glass_bottle.png",
 	wield_image = "vessels_glass_bottle.png",
 	paramtype = "light",
 	is_ground_content = false,
 	walkable = false,
 	selection_box = {
 		type = "fixed",
-		fixed = {-0.25, -0.5, -0.25, 0.25, 0.4, 0.25}
+		fixed = {-0.25, -0.5, -0.25, 0.25, 0.3, 0.25}
 	},
 	groups = {vessel=1,dig_immediate=3,attached_node=1},
 	sounds = default.node_sound_glass_defaults(),
@@ -103,7 +103,7 @@ minetest.register_node("vessels:drinking_glass", {
 	walkable = false,
 	selection_box = {
 		type = "fixed",
-		fixed = {-0.25, -0.5, -0.25, 0.25, 0.4, 0.25}
+		fixed = {-0.25, -0.5, -0.25, 0.25, 0.3, 0.25}
 	},
 	groups = {vessel=1,dig_immediate=3,attached_node=1},
 	sounds = default.node_sound_glass_defaults(),
@@ -122,14 +122,14 @@ minetest.register_node("vessels:steel_bottle", {
 	description = "Heavy Steel Bottle (empty)",
 	drawtype = "plantlike",
 	tiles = {"vessels_steel_bottle.png"},
-	inventory_image = "vessels_steel_bottle_inv.png",
+	inventory_image = "vessels_steel_bottle.png",
 	wield_image = "vessels_steel_bottle.png",
 	paramtype = "light",
 	is_ground_content = false,
 	walkable = false,
 	selection_box = {
 		type = "fixed",
-		fixed = {-0.25, -0.5, -0.25, 0.25, 0.4, 0.25}
+		fixed = {-0.25, -0.5, -0.25, 0.25, 0.3, 0.25}
 	},
 	groups = {vessel=1,dig_immediate=3,attached_node=1},
 	sounds = default.node_sound_defaults(),