Impyla

------
* **Improvements**
- Fix schema description returns for HiveServer2 when using dot in naming convention.
- Extensions to SQLAlchemy ImpalaDLLCompiler to support Alembic schema migrations
- Add impala4 sqlalchemy dialect for Impala >= 4.0

* **Bug Fixes**
- Fix regression in 445 (non-valid utf-8 strings handling in Python 3)

------
* **Improvements**
- Speed up fetchmany() and fetchall()
- Avoid unnecessary GetOperationStatus RPCs
- Bump fetch size to 10240 (from 1024)

* **Bug Fixes**
- Update setup.py: thrift-sasl is needed for ldap/plain authentication
- Hack to fix non-valid utf-8 stings handling in Python 3

------
* **Improvements**
- Unify Python 2 and 3 thrift handling and remove thriftpy2

------
* **Improvements**
- Add buffering to hs2-http (442)
- Remove references to 'sasl', always use 'pure-sasl' package

------
* **Improvements**
- Switch to using manylinux2010 docker build environment
- Upgrade to thrift-sasl 0.4.3a2

------
* **Bug Fixes**
- Add no_utf8strings to thrift compiler option (440)