move cypher config statement to Connection init()

Merge pull request #16 from WarpCloud/fix_schema_version

fix version mismatch for higher version

Merge pull request #15 from WarpCloud/graph_type_hash

- add __hash__ and __eq__ to GraphElement and Path

Merge pull request #14 from WarpCloud/add_schema_from_data_func

add getSchemaFromData()

Merge pull request #13 from WarpCloud/add_rowkey_hex_string

add rowkey hex string to vertex and edge object

Merge pull request #11 from Qi-weng/dev

Fix setup.py

Merge pull request #10 from Qi-weng/dev

Remove strong dependency on PySpark

Remove unnecessary restriction for Python3 version.

Fix readme syntax

- Assign pyspark lowest version

- Add installation instructions with Python 3.X