Improve startup speed

For RA:

What                | Before |  After
------------------- | ------ | ------
LoadMaps            |   1393 |    819
First main menu     |   3408 |   2897
Start a new game    |   2131 |    562
Back to main menu   |   2992 |   1587
Start a second game |   2136 |    506
Back to main menu   |   3035 |   1528