Fix type annotations on Node externs.

Notably, the Node methods cloneNode, insertBefore, removeChild, and replaceChild never return null.

I also changed various return types using the deprecated syntax {Node?} to {Node}.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=57702297
[FUZZER] Run the generated JavaScript with Node.js. Treat "undefined" and "NaN" as literals
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=57751544
Add @Deprecated annotations to declarations with @deprecated javadoc tags
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=57757147
[NEW TYPE INFERENCE]

Make unknown type names produce a warning rather than crash.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=57758109
Remove Alan from closure-compiler.pom
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=57762220