parse rule implementation

This is a propose to: https://github.com/ceylon/ceylon-sdk/issues/279, before spend more work on this i would like to have @luolong opnion/suggestions before be able to merge.

P.S.: Theres another issue about how to load de the resources, but it envolves a lot of decisions and maybe work inside ceylon build, so for now Im including all the resources inside ceylon.time and when we have a better decision about how to handle this we can delete it and do the correct way.
What are you testing exactly here?

The way I understand, links are just time zone name aliases. If someone asks for the time zone "Egypt", then they get the same time zone as they would get if they asked for "Africa/Cairo" instead.

It is a simple `String->String` mapping. 

You do not need to test if a map works.
Neither should you test that a particular mapping that you've just read from some external source exists. You might trust the source, but can you trust that this mapping will last forever. Maybe it will. Maybe not.

You do not need to test that mapping works. `ceylon.language` tests should cover that for you...