Move FormatOptions and FileHeader to FormatSpec.

...android/inputmethod/latin/ExpandableBinaryDictionary.java

...com/android/inputmethod/latin/UserHistoryDictIOUtils.java

...oid/inputmethod/latin/makedict/BinaryDictInputOutput.java

...rc/com/android/inputmethod/latin/makedict/FormatSpec.java

...ndroid/inputmethod/latin/UserHistoryDictIOUtilsTests.java

...android/inputmethod/latin/makedict/BinaryDictIOTests.java

...c/android/inputmethod/latin/dicttool/DictionaryMaker.java