rearrange README
compile: factored out a compileUnsafe function
attributes: assign names to all returned functions
sort: simplified, removed TODO note

Sorting attribute selectors improves the querying performance, but the
overhead outweighs it.
sort: recognize parent selector (`<`)
sort: sort attributes

Apparently, not applying DeMorgan in the condition speeds things up
noticably. As a result, this happens to be a good idea.
compile: Use `compileUnsafe` in :not
compile: Use DomUtils.existsOne in :has
index: use `compileUnsafe` when selecting

requires DomUtils@1.4
package: 0.4.1, require domutils@1.4