[BtS] Multi-Building Unit Requirement 2016-10-05

This mod adds the ability to specify multiple required and optional buildings
needed to building units. Any buildings added in between the <PrereqBuildings>
tag will now be required to build the unit. One of the buildings added in
between the <PrereqOrBuildinges> tag will now be required to build the unit.

For instance the updated battleship definition using the new tags looks like:


-----Notes to Modmakers-----

If you want to use this mod component in your mod I have tried to make things
as easy as possible for you. In the XML files I have added
<!-- Multi-Building Unit Requirement Start --> and
<!-- Multi-Building Unit Requirement End --> in all of the places where
changes were made. In the SDK files I have added
// < Multi-Building Unit Requirement Start > and
// < Multi-Building Unit Requirement End > in all of the places where changes
were made.

-----Version Information-----
-----v0.3BtS------

- Updated to be compatible with Beyond the Sword v3.19 patch.



-----===Credits & Thanks===-----

- Exavier
     Composite Mod - readme.txt format

- Doronron
     For proposing this mod.