Upgrade to Solr 4.6.0

As the title says. Still need to benchmark, but the tests pass.

```
Test Results:
yz_wm_extract_test-bitcask   : pass
yz_stat_test-bitcask         : pass
yz_solr_start_timeout-bitcask: pass
yz_siblings-bitcask          : pass
yz_security-bitcask          : pass
yz_schema_admin-bitcask      : pass
yz_pb-bitcask                : pass
yz_monitor_solr-bitcask      : pass
yz_mapreduce-bitcask         : pass
yz_languages-bitcask         : pass
yz_index_admin-bitcask       : pass
yz_fallback-bitcask          : pass
yz_errors-bitcask            : pass
yokozuna_essential-bitcask   : pass
aae_test-bitcask             : pass
---------------------------------------------
```

This also includes changes made in #232 as they were required to upgrade.