Limit texture size (#6)

* whitespace and minetest. -> core.

- use same whitespace style throughout and fix some indents.
- change from minetest. to core. namespace.

* Update Readme: Minetest -> Luanti

* add luacheck

* update optional depends

* luacheck cleanups

- unused arguments
- shaddowed vars
- var redeclarations
- some whitespace involved in above lines

* clean close of file after reading

* avoid duplicate code

save some lines and some extra method calls.

* avoid error: "unknown global"

* stray whitespace fixups

* whitespace: switch all files to same indent character

tabs -> spaces

* refactor weird declaration

* whitespace: two stray spaces

...that slipped through the cracks on previous whitespace edit

* fix shaddowing global table

* reduce amount of times transformation string is calculated

* use ipairs feature

or use the faster repeat-until-loop

* cap max amount of layers

fixes #5

* fix #5 make transform history non-global

fixes #5
transformation history was shared by all users and kept growing as it
was never truely reset. Every time a user
used a banner a white background was dumped on top of the
stack making it possible to crash the server through an
overflow to core.serialize() function.

* minimize metadata size

also changed banners.max_transformations to
banners.max_undo_levels and lowered the value substantially.

* add versioning

* add recoverable per player history with saved colour

* rename update_all -> update_preview_inv

since it isn't updating everything, only
the preview and the inventory item

* dynamically update masks

to reflect the currently selected colour.

items.lua

@@ -2,44 +2,35 @@
 
 -- items
 
-minetest.register_craftitem("banners:banner_sheet",
-    {
-        groups = {},
-        description = "Banner sheet",
-        inventory_image = "banner_sheet.png",
-        stack_max = 1,
-        metadata = "",
-    }
-)
+core.register_craftitem("banners:banner_sheet", {
+    groups = {},
+    description = "Banner sheet",
+    inventory_image = "banner_sheet.png",
+    stack_max = 1,
+    metadata = "",
+})
 
-minetest.register_craftitem("banners:wooden_pole",
-    {
-        groups = {},
-        description = "Wooden pole",
-        inventory_image = "wooden_pole.png"
-    }
-)
+core.register_craftitem("banners:wooden_pole", {
+    groups = {},
+    description = "Wooden pole",
+    inventory_image = "wooden_pole.png"
+})
 
-minetest.register_craftitem("banners:wooden_base",
-    {
-        groups = {},
-        description = "Wooden base",
-        inventory_image = "wooden_base.png"
-    }
-)
+core.register_craftitem("banners:wooden_base", {
+    groups = {},
+    description = "Wooden base",
+    inventory_image = "wooden_base.png"
+})
 
-minetest.register_craftitem("banners:steel_pole",
-    {
-        groups = {},
-        description = "Steel pole",
-        inventory_image = "steel_pole.png"
-    }
-)
+core.register_craftitem("banners:steel_pole", {
+    groups = {},
+    description = "Steel pole",
+    inventory_image = "steel_pole.png"
+})
+
+core.register_craftitem("banners:steel_base", {
+    groups = {},
+    description = "Steel base",
+    inventory_image = "steel_base.png"
+})
 
-minetest.register_craftitem("banners:steel_base",
-    {
-        groups = {},
-        description = "Steel base",
-        inventory_image = "steel_base.png"
-    }
-)