Added support multiple units of time for max_time

[christopherbunn]

Resolves #74

[codecov]

Codecov Report

Merging #125 into master will increase coverage by 0.13%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #125      +/-   ##
==========================================
+ Coverage   93.94%   94.07%   +0.13%     
==========================================
  Files          54       55       +1     
  Lines        1403     1434      +31     
==========================================
+ Hits         1318     1349      +31     
  Misses         85       85

Impacted Files	Coverage Δ
evalml/models/auto_base.py	92.45% <100%> (+0.14%)	⬆️
evalml/utils/__init__.py	100% <100%> (ø)	⬆️
evalml/utils/convert_time.py	100% <100%> (ø)
evalml/tests/automl_tests/test_autoclassifier.py	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1fc3d36...05656ae. Read the comment docs.

[kmax12]

LGTM

[angela97lin]

Really minor but I think this will raise the AssertionError when given a string like '20 s' due to the if unit[-1] == 's': unit = unit[:-1] check?

[christopherbunn]

@angela97lin Good catch, I'll push an update to this branch.