Performance Improvements

[vlozko]

Added perfromance improvements by:

• Better checking for context invalidation. If certain behaviors are added to a layout but there are no index paths that would need invalidation by the behaviors, the context shouldn't invalidate.
• Removing excessive sorting when creating BrickRangeDimensions (dimension pairs now have to be provided in minimum size order)
• Adding a custom height provider for generic brick cells. This will be helpful for generic brick cells that want to use its own size computation rather than rely on auto layout.

[codecov-io]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@9fb4236). Click here to learn what that means. The diff coverage is 97.61%.

@@            Coverage Diff            @@
##             master     #182   +/-   ##
=========================================
  Coverage          ?   93.47%           
=========================================
  Files             ?       40           
  Lines             ?     4386           
  Branches          ?      357           
=========================================
  Hits              ?     4100           
  Misses            ?      285           
  Partials          ?        1

Impacted Files	Coverage Δ
Source/Layout/BrickLayoutSection.swift	92.78% <ø> (ø)
Source/Behaviors/BrickLayoutBehavior.swift	100% <100%> (ø)
Source/Behaviors/CardLayoutBehavior.swift	87.5% <100%> (ø)
Source/Behaviors/SpotlightLayoutBehavior.swift	100% <100%> (ø)
Source/Behaviors/StickyLayoutBehavior.swift	96.38% <100%> (ø)
Source/Behaviors/OffsetLayoutBehavior.swift	96.15% <100%> (ø)
Source/Models/BrickDimension.swift	99.36% <100%> (ø)
Source/Layout/BrickFlowLayout.swift	91.09% <100%> (ø)
Source/Bricks/Generic/GenericBrick.swift	99.32% <87.5%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 9fb4236...3eef08e. Read the comment docs.