Elara

Description :
This is a breaking change

* `v0.4.x` moves away from `utf-8` encoded json based storage and stores data as bytes (uses `msgpack` dependency)
* Support for checksums to verify database file integrity
* updated tests

Every version after `v0.4.0` will use the same storage method thus breaking changes w.r.t this may be unlikely.
To safeguard data, its better to **export all existing data** from any existing database file before upgrading Elara. (use `exportdb(export_path)`).

Description :

* `v0.2.1` and earlier used a mix of `ascii` and `base64` encoding. `v0.3.0` uses `utf-8` encoding instead.
* To safeguard data, its better to export all existing data from any encrypted file before upgrading.
You can then use the `securedb()` method to re-encrypt it.

This release is a breaking change from `v0.2.x`.

Description :
* `incr(key, val=1)` and `decr(key, val=1)` added with tests

No breaking change.

Description -
* Improved support for in-memory caching :
- Includes a `cull()` function that deletes stale keys. Key access is tracked using the LRU principle
- `getkeys()` returns all the keys in the database ordered by most recently accessed.
* Updated tests for LRU
* Updated documentation for cache

No breaking changes were made in this update.