Add point property

[Sedictious]

No description provided.

[codecov-io]

Codecov Report

Merging #25 into master will decrease coverage by 0.36%.
The diff coverage is 98.14%.

@@            Coverage Diff             @@
##           master      #25      +/-   ##
==========================================
- Coverage   97.63%   97.27%   -0.37%     
==========================================
  Files           8        8              
  Lines         720      771      +51     
==========================================
+ Hits          703      750      +47     
- Misses         17       21       +4

Impacted Files	Coverage Δ
src/czml3/properties.py	99.28% <100%> (+0.07%)	⬆️
src/czml3/types.py	92.11% <91.66%> (-1.7%)	⬇️

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[astrojuanlu]

Perfect, merged!