Aerospike

Features
- Allow for a `None` set value for index creation methods. Support scans and queries against a namespace (with the set given as `None`). (AER-3462)
- Consistent [Unicode Handling](https://pythonhosted.org/aerospike/client.html#unicode-handling). Both str and unicode values are converted by the client into UTF-8 encoded strings for storage on the aerospike server. Read methods such as get(), query(), scan() and operate() will return that data as UTF-8 encoded str values. To get a unicode you will need to manually decode. **Note: this is a change in how string values are returned.**
- Fixed errors in the example scripts.

Fixes
- Fixed Issue 49 (AER-3537)
- Fixed a segfault which happened while scanning a namespace with `None` given for the set. (AER-3464)
- Fixed Issue 50 - test harness skips running security methods against community edition.

Features
- Upgraded to C client [3.1.11](http://www.aerospike.com/download/client/c/notes.html#3.1.11).
- Added support for [indexing complex types](https://pythonhosted.org/aerospike/client.html?#aerospike.Client.index_list_create) (lists, map) and for [querying](https://pythonhosted.org/aerospike/predicates.html?highlight=predicates.contains#aerospike.predicates.contains) against those secondary indexes. Those will become fully available with a near-future release of Aerospike server.

Fixes
- Raise a clear exception when bins are created with a name longer than 14 characters.
- Allow [Scan](https://pythonhosted.org/aerospike/scan.html) and [Query](https://pythonhosted.org/aerospike/query.html) objects to be reused.
- Raise an exception when trying to perform operations on an unconnected client (rather than segfaulting :grimacing: ).

- Implemented support for global policies through the client config.
- An AS_BYTES_BLOB will be set to a bytesarray if no deserializer is set.
- **Note:** the signatures for the following methods have been modified to make them more consistent: get_nodes(), info(), info_node(). See: [aerospike.Client](https://pythonhosted.org/aerospike/client.html?highlight=info#aerospike.Client.info)

- Upgraded to C client 3.1.8
- Fixed [Issue 38](https://github.com/aerospike/aerospike-client-python/issues/38)
- Fixed [Issue 40](https://github.com/aerospike/aerospike-client-python/issues/40)
- Fixed [Issue 41](https://github.com/aerospike/aerospike-client-php/issues/41). The [increment()](https://github.com/aerospike/aerospike-client-python/blob/master/doc/increment.md) method is **modified** to reflect the behavior of the C client (aka _upsert_)
- Fixed bugs where batch-operations were not showing the digest part of the key tuple. **Requires server version >= 3.5.3**