switch from levigo (cgo) to goleveldb (native)

Godeps/Godeps.json

...thub.com/blevesearch/bleve/index/store/goleveldb/batch.go

...hub.com/blevesearch/bleve/index/store/goleveldb/config.go

...b.com/blevesearch/bleve/index/store/goleveldb/iterator.go

...hub.com/blevesearch/bleve/index/store/goleveldb/reader.go

...thub.com/blevesearch/bleve/index/store/goleveldb/store.go

...hub.com/blevesearch/bleve/index/store/goleveldb/writer.go

Godeps/_workspace/src/github.com/golang/snappy/.gitignore

Godeps/_workspace/src/github.com/golang/snappy/AUTHORS

Godeps/_workspace/src/github.com/golang/snappy/CONTRIBUTORS

Godeps/_workspace/src/github.com/golang/snappy/LICENSE

Godeps/_workspace/src/github.com/golang/snappy/README

Godeps/_workspace/src/github.com/golang/snappy/decode.go

Godeps/_workspace/src/github.com/golang/snappy/encode.go

Godeps/_workspace/src/github.com/golang/snappy/snappy.go

Godeps/_workspace/src/github.com/jmhodges/levigo/.gitignore

Godeps/_workspace/src/github.com/jmhodges/levigo/LICENSE

Godeps/_workspace/src/github.com/jmhodges/levigo/README.md

Godeps/_workspace/src/github.com/jmhodges/levigo/batch.go

Godeps/_workspace/src/github.com/jmhodges/levigo/cache.go