ADD: support for S letter command

[ldevillez]

Description

S command were not supported in SVG2tikz. Inkex seems to do all the work to compute the points for the S command as for a C command. S and C commands are using the same logic

Fixes #210

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested on the svg of #210
New test using part of the logo included in the code

Checklist:

• My code follows the style guidelines of this project (black/pylint)
• I have updated the changelog with the corresponding changes
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
1120	1112	99%	0%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
svg2tikz/tikz_export.py	99%	🟢
tests/test_complete_files.py	99%	🟢
TOTAL	99%	🟢

updated for commit: 0040180 by action🐍