Add support for TIME WITHOUT TIME ZONE

[HerveMignot]

Summary

Add support for TIME WITHOUT TIME ZONE syntax

Added

• Add TIME WITHOUT TIME ZONE to TIME conversion to BQ type
• Add corresponding test as a subcase for TIME

[codecov]

Codecov Report

Merging #77 (ae64e17) into master (a1cea99) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #77   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         2           
  Lines          391       391           
=========================================
  Hits           391       391           

Impacted Files	Coverage Δ
ddlparse/ddlparse.py	100.00% <100.00%> (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 a1cea99...ae64e17. Read the comment docs.

[coveralls]

Coverage remained the same at 100.0% when pulling ae64e17 on HerveMignot:master into a1cea99 on shinichi-takii:master.

[HerveMignot]

Not sure why Travis fails in 3.7... Seems to be related to CodeClimate.