Refactor schema backward compatibility check

1. Fix a bug that will leave a store created even when exception has been thrown
2. Consolidate strings used by tests
3. Consolidate backward compatiblity check into StoreDefinitionUtils
Changed setReadOnly(true) -> setReadOnly(false) to prevent writing file summary fail when during bdb conversion
Merge pull request #169 from jameswu0629/bdb-conversion-0.9x-1.6.x

Changed setReadOnly(true) -> setReadOnly(false) to prevent writing file summary fail when during bdb5 conversion
Updating .classpath with new tusk jar
Added scala build support
Added Scala code for REPL
Made bin/run-class.sh compatible with scala shell
Changed files to work with updated source
Delete buildLog

Unnecessary for distribution
Adding checks to validate Avro schema during add-store
Added shell script to launch voldemort's scala shell
Added shell script to launch voldemort's scala shell & added jar files
Replace keySet() with entrySet() in validateAllAvroSchemas
Merge branch 'master' of github.com:bhsaurabh/voldemort
Made scala shell script more robust
Reverted run-class.sh to original
Merge branch 'scala-shell'
Removed unnecessary comment
Merge branch 'scala-shell'
Removed unnecessary comment in run-class.sh
Reverted javac version to 1.5 in build.properties