Add remaining GBA Memory Blocks (minus external memory)

[kendalharland]

• Some cleanup up in memory.dart
• Account for blank sections between blocks

[kendalharland]

Looks like the dev channel build is failing due to this line in package:presubmit https://github.com/matanlurey/presubmit.dart/blob/master/lib/src/plugins/analyzer.dart#L79

Must be a breaking change to the dart analyzer output. presubmit will have to be fixed before this can go in.

[matanlurey]

Looking at failure.

[matanlurey]

@kharland Try now - I updated presubmit for dev support.