Added statistics to Parquet pages and rowGroups
Addresses some initial comments. Javadocs, removed StatsHelper
Merge branch 'master' of github.com:egonina/parquet-mr into stats

Conflicts:
	parquet-hadoop/src/main/java/parquet/hadoop/ParquetInputSplit.java
Added licence to new files
Refactored the *Statistics classes to reuse more code. Added Binary compareTo methods
Added hashCode() method for Statistics class
Added length check for comparing two byte arrays
Adding back the Page() and writePage() methods for backward-compatibility
The methods now pass an empty Stats object downstream
Merge branch 'master' of https://github.com/Parquet/parquet-mr into stats

Conflicts:
	parquet-hadoop/src/main/java/parquet/hadoop/metadata/ColumnChunkMetaData.java
	parquet-hadoop/src/test/java/parquet/hadoop/TestInputFormat.java
adding 1.4.1 as previous version
previous version to 1.4.2
Merge branch 'master' of https://github.com/Parquet/parquet-mr into stats

Conflicts:
	parquet-hadoop/src/main/java/parquet/hadoop/metadata/ColumnChunkProperties.java
	pom.xml
adding back the parquet-hadoop methods that don't have statistics parameters, for backward comp
Merge pull request #338 from egonina/stats

Added statistics to Parquet pages and rowGroups