Pymapd

This release adds ability to define functions at runtime that run inside of OmniSci via LLVM. This functionality is still experimental, and currently does not work on the Windows operating system. Future development for Windows is planned.

Fixed issue with `conn.execute()` and a `parameters` argument, where having leading spaces caused an upload error.

Also, moved the minimum allowed pyarrow to 0.12, as a reflection that cudf 0.8 is supported for `select_ipc_gpu`.

_Notable PRs_

Increase pyarrow minimum to 0.12 (258)
Ensure execute() 'operation' argument trimmed before sending (268)

This enables pymapd's connection object to consume the necessary parameters required to connect to OmniSciDB via a recently implemented binary Thrift over TLS protocol.

Also fixes build issue with v0.14.0, where package only installs using `pip install -e .` instead of from PyPI.

This release updates the Thrift bindings to the upcoming release of OmniSci 4.8. For most people, this should be an invisible change, with the exception of the new namespacing of the Thrift files. If you have built anything on the Thrift internals of this library, then you will need to note the new library name locations.

Fixed a bug with datetimes with timezones. All timezone dates will be converted to UTC before uploading into OmniSci (as the database expects to receive).

_Notable PRs_
Update Thrift to 4.8 with namespacing (252)
Add support for all timezones for timestamp (254)

In this release, the biggest user facing changes are changing the context manager to return self, not the next level down. For example, for c in connect() now returns a Connection object instead of a Cursor (e.g. self.cursor()).

The CI environment was also switched from Travis CI (free) to Jenkins (hosted on OmniSci servers). This allows for testing on CPU and GPU, for better monitoring of important functionality.

Notable PRs
Switch connection context manager to self (237)
Update connection parameters (239)
New test pipeline (240)
Don't close connection object if created using sessionid (243)

Using Thrift definitions from OmniSci 4.6.1 added new Python modules, which were not added to setup.py in pymapd 0.12