[feritcemkahraman]

Media queries using points, picas, or dots per centimeter can compare against the wrong breakpoint. For example, (width: 72pt) currently does not match a width of 96px.

Use the CSS unit ratios: 72pt = 6pc = 96px and 100dpcm = 254dpi. Both query expressions and supplied device values go through these conversions. Also correct the existing expectation for 75dpcm exceeding 72dpi.

Fixes #12.

References: https://www.w3.org/TR/css-values-4/#absolute-lengths and https://www.w3.org/TR/css-values-4/#resolution

Validation:

• Existing baseline: 47 tests pass.
• Regression tests before the source fix: 46 pass, 4 fail.
• After the fix: all 50 tests pass with 100% statement, branch, function, and line coverage.
• Tests check equivalent mixed units in both operands and min/max boundaries.
• node node_modules/istanbul/lib/cli.js cover -- ./node_modules/mocha/bin/_mocha test/ --reporter dot
• git diff --check passes.