Sticker-convert

Fix unable to import tgs

- Fix unable to upload stickers
- Fix Signal stickers all being recompressed
- Fix image fps report as 1 instead of 0
- Fix image duration report as 1 instead of 0
- Fix unable to import frames if video format is yuv420p
- Fix unable to import frames if image is not in RGBA mode
- Safer handling for getting info about image
- Tuning default compression parameters to prevent failure
- Cleanup code for verifying file extension

- Use imagequant for image quantization
- Add quantize_method parameter for choosing quantization method with
- Add power parameters for preventing some parameter from reduced too soon
(fps_power, res_power, quality_power, color_power)
- Try to keep fps high by adjusting fps_power
- Remove imageio dependency
- Ensure resolution is even for exported stickers
- Reduce unecessary file reads for getting media info
- Lazy load modules for faster load time
- Allow reading number of frames from metadata in pyav if present
- Cleanup code in codec_info
- sanitize_filename function separate from FormatVerify

- Fix incorrect conversion of YUV to RGB
- Faster fps determination
- Use libvpx for demux vp8 during fps calculation

- Fix 114
- Fix yuva420p webm causing crash
- More reliable way of getting fps from pyav
- Use libvpx for vp8
- Fix frames_drop() with duration_min == 0
- Add check for same input and output directory

- Update apngasm-python and nuitka (Proper fix for https://github.com/laggykiller/sticker-convert/issues/110)