Removing CollectionBuffer/ManagedBuffer from internals.

[tonystone]

I've switched to a straight Array implementation since the array gives us numerous benefits for cleaner re-use and centralization of code for operations like intersection, etc. We still maintain the benefits of the managed buffer since each Array (which is the entire internal representation of the geometries) creates a managed buffer behind the scenes.

[codecov-io]

Codecov Report

Merging #174 into master will decrease coverage by 4.25%. The diff coverage is 81.29%.

@@            Coverage Diff             @@
##           master     #174      +/-   ##
==========================================
- Coverage    96.6%   92.34%   -4.26%     
==========================================
  Files          41       40       -1     
  Lines        3178     2718     -460     
  Branches      187      149      -38     
==========================================
- Hits         3070     2510     -560     
- Misses         97      206     +109     
+ Partials       11        2       -9

Impacted Files	Coverage Δ
Sources/GeoFeatures/Geometry.swift	3.75% <0%> (-0.15%)	:arrow_down:
...rces/GeoFeatures/GeometryCollection+Geometry.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/Polygon+Surface.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/LinearRing.swift	100% <100%> (+0.59%)	:arrow_up:
Sources/GeoFeatures/LinearRing+Geometry.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/MultiLineString+Curve.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/MultiPolygon+Geometry.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/LinearRing+Curve.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/MultiLineString+Geometry.swift	100% <100%> (ø)	:arrow_up:
Sources/GeoFeatures/LinearRing+Surface.swift	100% <100%> (ø)	:arrow_up:
... and 11 more