use ImageBase.restrict

[johnnychen94]

The tests for restrict are still kept here; more test cases are added to ImageBase side.

closes #69

[codecov]

Codecov Report

Merging #127 (1ea2653) into master (328a4b8) will decrease coverage by 2.15%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #127      +/-   ##
==========================================
- Coverage   93.90%   91.74%   -2.16%     
==========================================
  Files           8        8              
  Lines         328      218     -110     
==========================================
- Hits          308      200     -108     
+ Misses         20       18       -2     

Impacted Files	Coverage Δ
src/ImageTransformations.jl	83.33% <ø> (ø)
src/resizing.jl	100.00% <100.00%> (+1.19%)	⬆️

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