add a validation setting to OutputFormat
Merge branch 'master' of github.com:Parquet/parquet-mr into add_validation_setting

Conflicts:
	parquet-hadoop/src/main/java/parquet/hadoop/ParquetOutputFormat.java
	parquet-hadoop/src/main/java/parquet/hadoop/ParquetRecordWriter.java
	parquet-hadoop/src/main/java/parquet/hadoop/ParquetWriter.java
better error message and javadoc
Merge pull request #53 from Parquet/add_validation_setting

add a validation setting to OutputFormat