Plumb OriginalType

I noticed that after writing a Parquet file and then reading it, all the annotations were dropped from the schema. I found that the OriginalTypes were not being plumbed through to the converted_type fields in the SchemaElements in the metadata and vice versa.

I made some changes to plumb the OriginalTypes in the schema through to the file so that the annotations are preserved.

Note: this pull request depends on the pull request Parquet/parquet-format#67, which adds ENUM to ConvertedType. This may result in Travis build breaks before Parquet/parquet-format#67 is merged and a new snapshot with the changes are available in the Maven repositories.