[Feature Request] Support for Remapping Packages

I was working on https://github.com/openfl/openfl-js/pull/11, but realized that, if a library exports itself under 2 namespaces like that, users will stumble upon issues REALLY quickly.
One example of this is, say the library exports itself as openfl.* and flash.*, but another library depends on it compiles using the openfl.* version of classes, this will immediately cause issues to the end user if they want to use the flash.* version, because e.g. flash.display.Bitmap isn't the same as openfl.display.Bitmap to the compiler.
I believe for this reason, there should be a feature similar to Haxe's --remap compiler flag, that allows a package to be imported under another name, for compatibility reasons.