[MRG] Add support to read from url

[vinayak-mehta]

Closes #91.

[codecov-io]

Codecov Report

Merging #236 into master will decrease coverage by 0.34%.
The diff coverage is 79.59%.

@@            Coverage Diff             @@
##           master     #236      +/-   ##
==========================================
- Coverage    87.5%   87.15%   -0.35%     
==========================================
  Files          13       13              
  Lines        1416     1456      +40     
  Branches      333      338       +5     
==========================================
+ Hits         1239     1269      +30     
- Misses        121      128       +7     
- Partials       56       59       +3

Impacted Files	Coverage Δ
camelot/io.py	100% <ø> (ø)	⬆️
camelot/handlers.py	82.92% <100%> (+0.42%)	⬆️
camelot/utils.py	80.32% <73.68%> (-0.93%)	⬇️

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