*Added AES128 Encryption
*Added AES258 Encryption/Decryption
*Added SHA256
*Added SHA512
*Added class to handle 8 byte integers and associated bit operations
*Added SHA384
*Added routines to handle new algorithm and perform PDF2.0 hashing.
When decoding a stream, the decode buffer is often grown multiple times, its
byte size increasing like so: 512, 1024, 2048, etc. This patch estimates the
minimum size in advance (using the length of the encoded stream), often
allowing the smaller sizes to be skipped. It also renames numerous |length|
variables as |maybeLength| to make it clear that they can be |null|.
I measured this change on eight documents. This change reduces the cumulative
size of decode buffer allocations by 0--32%, with 10--20% being typical. This
reduces peak RSS by 10 or 20 MiB for several of them.
