Refactor math, cell and props

[johnfercher]

Description

• Refactor math to be agnostic to provider
• Refactor cell and props to use pointers instead to copy data

Benchmark

• min: 5008.527149, max: 6138.680649, avg: 5528.973213 (Old)
• min: 4720.954979, max: 5639.864653, avg: 5298.453789 (New)
• min: 6% better, max: 8.8% better, avg: 4.3% better

Checklist

check with "x", if applied to your change

• All methods associated with structs has func (s *struct) method() {} name style.
• Wrote unit tests for new/changed features.
• Updated docs/doc.go
• Updated pkg/pdf/example_test.go
• Updated README.md
• Updated all examples inside internal/examples
• New public methods/structs/interfaces has comments upside them explaining they responsibilities
• Executed make dod with none issues pointed out by golangci-lint and goreportcard-cli

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (v2@f925b6e). Click here to learn what that means.
Patch has no changes to coverable lines.

Additional details and impacted files

@@          Coverage Diff          @@
##             v2     #312   +/-   ##
=====================================
  Coverage      ?   23.56%           
=====================================
  Files         ?       20           
  Lines         ?      968           
  Branches      ?        0           
=====================================
  Hits          ?      228           
  Misses        ?      734           
  Partials      ?        6           

Flag	Coverage Δ
unittests	23.56% <0.00%> (?)

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