Add Index / CSS / JS for Prime Number Test. Stable working condition

First version of my prime number testing is now uploaded. Bootstrap
files used. JS from winter cohort (count how many prime numbers are in
this array) used in this JS code. HTML is responsive. Future add-on is
a table that records the data.
Revert "Add Index / CSS / JS for Prime Number Test. Stable working condition"

This reverts commit 92a3824bd9cae1206089ba543972abe345af3410.
Merge branch 'master' into gh-pages