add several utility functions related to tables.

create api functions `any`, `every`, and `underride`.

`any` and `every` checks if a condition is true for any and every item
in a table, respectively.
`underride` returns a table that defaults to a provided table, for
items that aren't specified in the other provided table.

mods/bg_api/util_table.lua

@@ -26,3 +26,26 @@ function blockgame.shuffle (tab)
 	end
 	return result
 end
+
+function blockgame.any (tab, check)
+	for key, value in pairs(tab) do
+		if check(value, key, tab) then return true end
+	end
+	return false
+end
+
+function blockgame.every (tab, check)
+	for key, value in pairs(tab) do
+		if not check(value, key, tab) then return false end
+	end
+	return true
+end
+
+function blockgame.underride (tab, template)
+	local tab = tab or {}
+	local result = blockgame.shallow_copy_table(template)
+	for key, value in pairs(tab) do
+		result[key] = value
+	end
+	return result
+end