n#753460: Copying slides having same master page name.

Ported from: aa822c44b758fe312a3a052f890f53418adc5f6b

Change-Id: I36862355255222a36e4e10685741e0da67e8fbe7
Add append(bool) to OStringBuffer.
Force enums as ints - to avoid warning/errors.
Force int16 as int32
Move string hash function into String class.

hashCode() seems to do sampling while creating the hash.
hashCode64() will not.

Change-Id: Id30f5a2a774cf5244dbc00da9649e95a532484be
n#757432: Styles (rename &) copy to different decks.

Ported from: 9f8baf0ed263889e3e77ea12ccb908020fee05a8 and
a4cd841541a729d7b8126d27d91fa28e30b01403

Change-Id: If0e56cd8b2aab1ff4c6166b8c84a41b39c2f1414
String cleanups.

Ported from 4cf0d8edaf1581c42949ad2cbb40183a2f657ddd

Change-Id: I4aa32fdeafdd17135c56b9f113f1abd06df892cf
Stick to a single O[U]String hash function.

Ported from 98554820e6109c3e3f4ea83bf036d9f20ef1685e

Change-Id: I22a6ffd71828295e92798fb1201133c0a5e25eda