wrong text color for row select in demo

[BePo65]

I'm submitting a ... (check one with "x")

[x ] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here, post on Stackoverflow or Gitter

Current behavior in the demos for selection (single or multi row) the text in the selected row(s) is black (and thus not really readable).

Expected behavior The text should be white (as defined in the material.scss file)

Reproduction of the problem Problem can be seen in the demo side (http://swimlane.github.io/ngx-datatable/#single-selection)

What is the motivation / use case for changing the behavior? Better readability

Please tell us about your environment: using VScode V1.31.0

• Table version: V14.0.0

• Angular version: V7.1.0

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ] Tested with firefox V65.0 and Chrome V72.0.3626.96

• Language: [all | TypeScript X.X | ES6/7 | ES5] typescript@3.1.6

[BePo65]

Created a solution and will send pull request (hope this is ok for you)