remove use of coercion operators == and !=

The == and != operators use type coercion. This leads to inconsitent
results when type coerced to an unexpected result. Use the strict form
of the operators.

	modified:   src/dotplot2.js
remove extra whitespace and remove tabs

	modified:   src/dotplot2.js
	modified:   test/tester.html
	modified:   test/tester2.html