[Feature] Option name backwards compatibility

[trigg]

Currently, once an option is in use we are stuck with the name it has.

My proposal is a new tag <also> (or, potentially an attribute on the <option> of the same name

So, theoretically

    <option name="new_name" type="int">
      <also>old_name older_name</also>
      <default>10</default>
      <min>1</min>
      <max>20</max>
    </option>

Which would read from an ini file

[section]
new_name=5
old_name=15

Finding the value 5

and from a different config file

[section]
old_name=15

Finding the value 15