Add validation to the memory settings window.
Should assert:
- max memory is within (initial+earlyGen) ... ceiling
- initial, earlyGen >= Java's 64mb minimum
- initial > earlyGen (see below)
- values are numbers
Setting earlyGen equal to or higher than initial memory causes the game to crash with the following message -- which is not displayed to the user through either the launcher's output or its logging:
Error occurred during initialization of VM
Too small initial heap for new size specified