add test on leap years and value sanitization algorithm
tests of max number of days
check month range
Merge four volumechange tests into a single more comprehensive one
add tests for input type=week
Merge pull request #644 from deniak/date-leap-year

add test on leap years and value sanitization algorithm
fix link and use editor's draft
Merge pull request #648 from deniak/input-week

add tests for input type=week
Merge pull request #647 from foolip/volumechange

Merge four volumechange tests into a single more comprehensive one
Merge pull request #645 from deniak/input-month

check month range
Test non-support of more historical media features
Merge pull request #649 from foolip/historical-media-features

Test non-support of more historical media features