Merge pull request #231 from magro/master

Change KryoPool to interface + Builder, make SoftReferences optional.
Fix serializers reference
Merge pull request #233 from puneetlakhina/patch-2

Fix serializers reference
(*) Enhacements to DateSerializer: use identity comparison
(*) Enhacements to LocaleSerializer:
  - removed copy method, as Locale isImmutable
  - reordered and enhacements to the Locale constants search inside the create method
  - optimized write method: use writeAscii for language and country fields (not for variant)
Unit tests for DateSerializer and LocaleSerializer
DateSerializer and LocaleSerializer enhacements and tests

(*) Enhacements to DateSerializer: use identity comparison
(*) Enhacements to LocaleSerializer:
  - removed copy method, as Locale isImmutable
  - reordered and enhacements to the Locale constants search inside the create method
  - optimized write method: use writeAscii for language and country fields (not for variant)
(*) Added tests for DateSerializer and LocaleSerializer
DateSerializer and LocaleSerializer enhacements and tests

(*) Enhacements to DateSerializer: use identity comparison
(*) Enhacements to LocaleSerializer:
  - removed copy method, as Locale isImmutable
  - reordered and enhacements to the Locale constants search inside the create method
  - optimized write method: use writeAscii for language and country fields (not for variant)
(*) Added tests for DateSerializer and LocaleSerializer
Fix a NPE
Small optimization
Override writeChar and readChar methods to use unsafe: writeChar now performs about 125% faster and readChar 10% faster than overriden safe versions.
Remove unnecesary code
Merge pull request #240 from serverperformance/unsafe-enhacements

Unsafe IO optimizations: Override writeChar and readChar methods to use unsafe
Merge pull request #237 from serverperformance/default-serializers

DateSerializer and LocaleSerializer enhacements and tests
BigIntegerSerializer, BigDecimalSerializer, TreeMapSerializer and TreeSetSerializer optimizations and enhacements:
  - Proper handle of subclasses (Fix #166)
  - Small optimizations for common BigDecimal and BigInteger constants (Fix #238)
  - Unit test to avoid regression of PermGen leaks (ensure fix of #170 contributed by #173)
Merge pull request #245 from serverperformance/master

BigIntegerSerializer, BigDecimalSerializer, TreeMapSerializer and TreeSetSerializer optimizations and enhacements
Fixed DeflateSerializer.

Can't use Kryo to write the object. Kryo has already registered a reference ID for the object, so using Kryo again would only write the reference.
end() for deflater and inflater.
Fixed #248. There was a bug in the buffer resizing code.
Update README and CHANGES for 3.0.0 release