Fix getindex with extra dims

[jipolanco]

Fixes #79

[codecov-commenter]

Codecov Report

Merging #80 (f6fbe52) into master (15fa3f9) will decrease coverage by 0.11%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #80      +/-   ##
==========================================
- Coverage   97.01%   96.90%   -0.11%     
==========================================
  Files          22       22              
  Lines        1239     1229      -10     
==========================================
- Hits         1202     1191      -11     
- Misses         37       38       +1     

Impacted Files	Coverage Δ
src/arrays.jl	93.96% <100.00%> (-1.12%)	:arrow_down:

... and 3 files with indirect coverage changes