EXP-62. Add support for column filters defined in a
ModelEnvironment.

This commit defines Express column filters as Avro records and in a
ModelEnvironment, which can be converted into Kiji column filters
used in a Kiji data request.

Reviewed by: kiyan
EXP-108. Deprecate and remove `express script`

issue: https://jira.kiji.org/browse/EXP-108
review: https://review.kiji.org/r/779
EXP-146. Fall back to $HADOOP_HOME/lib/native/ for native libraries.

If an architecture-specific subdirectory does not exist, check one
level higher in the directory structure.
scratch work
EntityIdComponents
src/main compiles
partway through making tests pass
More tests pass
Almost all tests working
scratch work
more debugging work
Tests pass (was hashed vs formatted row keys)
Started equals method. needs tests. and integration tests for the joins
starting equals methods, starting unit tests.
blah
blah
may have fixed the equals method
Compare method
Join test passes in local mode.
Works when testing manually, but not in test framework