Code restructure
Some refinements on the hadoop input format

This is a combination of commits:
* make hadoop-compat compatible to hadoop yarn and remove org.apache.hadoop code
* Extended usercode wrapper, fixed IF serialization
* introduce pluggable type converter
* make the converter interface more generic; (hopefully) improved fetching logic
Added convenience constructor to RemoteExecutor
Reorganized .gitignore.
quick fix for build error
Added code for reflective avro types.
Adding comments to removeField and uncommenting its test method
Moving all annotations to Java API
removeField method in Record class
Moving all annotations to Java API
Moving all annotations to Java API
Moving all annotations to Java API
Merge branch 'master' of https://github.com/jcamachor/stratosphere
Moving all annotations to Java API
Merge branch 'master' of https://github.com/jcamachor/stratosphere