Fix extraneous non-unix line endings (`^M`) in checkstyle and strip extraneous spaces.
Change AutoServiceProcessor to not use `\` as a separator in `META-INF/services/` on Windows. It doesn't work.

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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=60653143
Two changes merged together from commit surgery.
   * Make it an error for an `@AutoValue` class to inherit from `Annotation` if the class does not define or inherit both `hashCode()` and `equals(Object)`
   * In `@AutoValue` classes, recognize any annotation called `@Nullable`, not just `@javax.annotation.Nullable`.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=61434773
MOE_MIGRATED_REVID=60653207