Convert al_* functions to properties using workaround in #3
Rename functions to avoid overloading

As a workaround for this bug:
https://github.com/indragiek/SwiftAutoLayout/pull/4#issuecomment-4679494
4

rdar://17412596
Update comments to include radar/repro details
Update README
Merge pull request #4 from indragiek/al-properties

Convert al_* functions to properties using workaround in #3