MList backed by java.util.List and change to CHash

Hi,

I have implemented an MList (array) which is backed by a java.util.List. 

It is lib/MJUList.java and extends MList. I had to change MList to make most methods not final. Therefore I had to make changes to the yeti-lib directly - instead of just creating my own class.

There is also an updated to std.yeti with the customArray function and some tests

Additional I changed CHash, to take not only a constructor function but also a function to copy the j.u.Map. I think this is necassery if I want to wrap an already populated Map. So there are two functions one for the orignal Map and one to copy the original Map.

Please see these as of course as just proposals. I would be happy if you put it into yeti but there is no need to do so if you don't want, because I can add my own CHash and MJUList as an extra api. However it would be great if the changes to MList would be added to the yeti-lib, because otherwise I can not extend MList meaningful. 

Thanks,
Christian