Merge pull request #4 from asacamano/master

Initialial layout including readme, contributing, and hacking files.
added link to John Maheswaran's webpage in contributors file
created initial class files for Key KeyVersion AESKey (not implemented yet)
restructed key version hierarchy so AESKey extends SymmetricKey which extends KeyVersion
Added K2Exception super-class.
AES key implementation with methods to encrypt and decrypt byte arrays
changed to use encrypt string method
moved files to new package. added tests for AES key
removed duplicate files for package restructuring
added author to AESKeyTest
added Apache licenses and Google copyright notice to source files
removed old comment
Update README.md

More spelling fixes
Added basic message internationalization framework (adapted from Keyczar).
Merge remote-tracking branch 'upstream/master'
Update HACKING.md

Added unit testing book reference.
Merge remote-tracking branch 'upstream/master'
Added unit test for K2Exception.
Merged conflict
Syncing with layout of internal repo.