Some Int-based tests, and fixes to work with 0.9.0-SNAPSHOT

- Updated key-value tests to also allow aggregate and sort on ints
- Updated SBT assembly to work properly with 0.8/0.9's assembly (the
  previous one crashed due to an issue with META-INF/LICENSE)
- When linking with Spark, don't package *all* the JARs in the Spark
  directory; just take its assembly JAR
Link with Spark more efficiently in shark-tests too
Fix test suite and some paths that included Scala versions
Merge pull request #9 from mateiz/fixes

Some Int-based tests, and fixes to work with 0.9.0-SNAPSHOT