Kintree

Maintenance Release

* Improved image download, see 77
* Switched from `request` to `urllib.request` library
* Added User-Agent support, for URL not resolving without
* Only two tries for the image download: first without (Digi-Key) then with User-Agent (Mouser & LCSC)
* Improved part compare with existing parts, see 78
* Compare with parts from the same category tree, not the parent category
* Prevent comparing parts with empty parameters (they were matching)
* For parts with empty parameters, also check the manufacturer data to avoid duplicates when searching the same MPN with different suppliers

KiCad v6

With the [release of KiCad version 6](https://www.kicad.org/blog/2021/12/KiCad-6.0.0-Release/), KiCad changed the symbol file format from combination of couple of files (`.lib`+`.dcm`) to a single, s-expression file (`.kicad_sym`). The KiCad library reader and writer tool was imported from [KiCad's library utils repository](https://gitlab.com/kicad/libraries/kicad-library-utils).

Because of limited maintenance bandwidth, Ki-nTree versions `0.5.x` and newer will only support KiCad version **6**. To keep using Ki-nTree with KiCad version **5**, use older `0.4.x` versions (pip install kintree==0.4.8).

This release also updated all dependencies and corrected the retrieval of Digi-Key categories due to a change of the Digi-Key API output.

Maintenance release
* Fixed KiCad website URLs to kicad.org
* Added CC0 license to KiCad templates
* Added mention to KiCad template paths in settings documentation
* Fixed 70 with 64 (thanks ad1217)
* Fixed 67 with 71
* Fixed 69 with 71

GUI Update
* Added taskbar logo
* Overall polishing:
* Added global UI settings
* Bigger & better font
* Aligned form fields

- Fixed broken [0.4.5](https://github.com/sparkmicro/Ki-nTree/releases/tag/0.4.5) release...
- Updated README

Maintenance Release
* Automatically update GUI version upon publishing: https://github.com/sparkmicro/Ki-nTree/pull/58
* Bug fix for empty list of parameters using LCSC API: https://github.com/sparkmicro/Ki-nTree/pull/60
* Now using PyPI version of Mouser API: https://github.com/sparkmicro/Ki-nTree/pull/61

Do Not Use
Use [0.4.6](https://github.com/sparkmicro/Ki-nTree/releases/tag/0.4.6) release instead