Some 2.0 projects fail to validate

[kchadha]

Maze Starter (#10128431) does not validate as a 2.0 project (and therefore doesn't load):

Relevant error:
"sb2Errors":[{"keyword":"required","dataPath":".info","schemaPath":"#/properties/info/required","params":{"missingProperty":"swfVersion"},"message":"should have required property 'swfVersion'"}]

[kchadha]

This project also doesn't load: #10003280 <--- penLayerMd5 can be null

"sb2Errors":[{"keyword":"type","dataPath":".penLayerMD5","schemaPath":"#/properties/penLayerMD5/type","params":{"type":"string"},"message":"should be string"}]

After fixing the above, we get:

"sb2Errors":[{"keyword":"required","dataPath":"","schemaPath":"#/required","params":{"missingProperty":"videoAlpha"}

[kchadha]

Also project #10128168

[kchadha]

10015857