Sort extracted styles using module import order

[kendrickw]

This PR fixes #96, and the solution is based heavily on the work by dnjstrom in #109

These changes correct the source ordering of the extracted styles in the minimal example from #108.

The rollup version in the devDependencies has been upgraded, so that the jest test would exercise the new code that has been added.

[codecov]

Codecov Report

Merging #143 into master will increase coverage by 0.11%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #143      +/-   ##
==========================================
+ Coverage   94.61%   94.73%   +0.11%     
==========================================
  Files           8        8              
  Lines         223      228       +5     
  Branches       77       78       +1     
==========================================
+ Hits          211      216       +5     
  Misses         12       12

Impacted Files	Coverage Δ
src/index.js	98.38% <100%> (+0.14%)	⬆️

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