Code optimizations for TextLiquidFill.

[awhitford]

• Changed _loadValue to be from 0 to 1 instead of 0 to 100 to avoid a division by 100.
• Removed unnecessary stop calls and null guards in dispose.
• Simplified calculations in _WavePainter.

[codecov]

Codecov Report

Merging #165 (8cc3f82) into master (df9c63a) will decrease coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #165      +/-   ##
==========================================
- Coverage   91.01%   90.92%   -0.09%     
==========================================
  Files           9        9              
  Lines         445      441       -4     
==========================================
- Hits          405      401       -4     
  Misses         40       40              

Impacted Files	Coverage Δ
lib/src/text_liquid_fill.dart	88.31% <100.00%> (-0.58%)	⬇️

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[aagarwal1012]

Code changes look good to me, but we should proceed towards updating readme and release v3.0.0.

[awhitford]

We should proceed towards updating readme and release v3.0.0.

Oh good -- I was unclear if you were sold on the 3.0 idea.

[aagarwal1012]

@awhitford, I really liked your suggested changes and I totally support the fact of releasing v3.0.0.