Make DateTimePicker respect dateLabel and timeLabel

[robert-lindstrom]

DateTimePicker now makes use of the dateLabel and timeLabel properties
of the object passed in the strings prop.

Q	A
Bug fix?	[X]
New feature?	[ ]
New sample?	[ ]
Related issues?	fixes #346

What's in this Pull Request?

DateTimePicker now uses the dateLabel and timeLabel properties of the object passed in the strings prop.

[codecov-io]

Codecov Report

Merging #347 into dev will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev     #347   +/-   ##
=======================================
  Coverage   72.88%   72.88%           
=======================================
  Files          17       17           
  Lines         767      767           
  Branches      149      149           
=======================================
  Hits          559      559           
  Misses        161      161           
  Partials       47       47

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[estruyf]

Thanks @robert-lindstrom!