[stats] fix ArithmeticDecoder zero-padding

Fix edge case in some cases where encoded input has fewer than 6 bytes and we get unlucky with underflow.  See comments in TestArithmeticCodec.testDecodeZeroPaddingRequired() for more details.
[maven-release-plugin] prepare release jcommon-parent-0.1.7
[maven-release-plugin] prepare for next development iteration
[Logger] Allow % character in logged messages

Change logging methods to not String.format() if there are no format args.  This avoids UnknownFormatConversionException when, e.g., logging a simple message that contains a %
[maven-release-plugin] prepare release jcommon-parent-0.1.8
[maven-release-plugin] prepare for next development iteration
remove String.format
Remove log4j dependency in code

This diff tries to remove log4j dependency in code and let the library
only depend on slf4j-api. I also removed a lot of logging statements
in unit test because in my opinion unit tests should only print
when the they fail.

Resolves #6
update facebook-oss-pom dependency version to 6

Version 5 does not work well with maven 3.1.0 since the plugin versions it refers to are known to have compatibility problems

Resolves #27
[maven-release-plugin] prepare release jcommon-parent-0.1.9
[maven-release-plugin] prepare for next development iteration