Revert pre-alpha 3.0.0 because I was supposed to push it to a branch.

This reverts commit cbf25999f0.

halyde/core/datatools.lua

@@ -0,0 +1,45 @@
+local conversionTables = {
+  ["bytes"] = {
+    ["B"] = 1,
+    ["KB"] = 1000,
+    ["MB"] = 1000000,
+    ["GB"] = 1000000000
+  }, ["bibytes"] = {
+    ["B"] = 1,
+    ["KiB"] = 1024,
+    ["MiB"] = 1048576,
+    ["GiB"] = 1073741824
+  }
+}
+
+function table.find(tab, item)
+  for k, v in pairs(tab) do
+    if v == item then
+      return k
+    end
+  end
+end
+
+function table.copy(orig)
+  local orig_type = type(orig)
+  local copy
+  if orig_type == 'table' then
+    copy = {}
+    for orig_key, orig_value in next, orig, nil do
+      copy[table.copy(orig_key)] = table.copy(orig_value)
+    end
+    setmetatable(copy, table.copy(getmetatable(orig)))
+  else -- number, string, boolean, etc
+    copy = orig
+  end
+  return copy
+end
+
+function convert(amount, fromUnit, toUnit)
+  for _, convTable in pairs(conversionTables) do
+    if convTable[toUnit] then
+      return amount / convTable[toUnit] * convTable[fromUnit]
+    end
+  end
+  return false, "unit does not exist"
+end