v0.5.0 release

First official release of the Ab-Initio version of Porechop.

New features (compared to native Porechop) includes:

• Automatic adapter sequence inference from read file (--ab_initio / -abi mode)
• Setting custom adapters from command line (--custom_adapters / -cap + adapter file)
• Possibility to ignore default database adapters (--discard_database / -dd)

Current work is stable enough to work in production,
but some changes need to be made before the release of the 1.0.0 version.

Here is a non exhaustive list of needed changes:

• Read loading / unloading optimization
• Unified file, reads and error handling for Porechop and ab-initio module
• Fully wrapping the approximated k-mer counter using shared objects
• Native MS Windows installation through setuptools and conda.
• More unit tests and integration tests