the numberOfPairs may not be negative when numberOfPairs*2 is negative
Merge pull request #289 from levelup/double-negative

the numberOfPairs may not be negative when numberOfPairs*2 is negative
Improve HttpResponseCache initialization speed.

Introduce a string-like class ByteString that works with raw
byte[]s and adds a few StringBuilder functions. Use it to
eliminate allocation of temporary objects in DiskLruCache.
Faster loading of cached https responses.

Avoid excessive memory allocation and copying around when
base64-decoding certificate data. Add some error checking.
Remove synchronization from StrictLineReader.