Allow to copy the profile

This is my attempt to fix #50. Seems to be working, but unfortunately I don't understand all the inner workings of hashdist yet. @dagss --- can you please review this PR?

What does the profile package do? Why would I want or do not want to include it? I noticed that when I include it, then it complains about not having some json file in there. So what I did is copy the "imports" stuff from the build and that way it doesn't seem to include the profile package and it works. I don't know if I included the imports correctly.

Another important problem: if I do:
```
$./update --copy ay
$ ls -ld aa/lib/python2.7/site-packages/matplotlib
lrwxrwxrwx 1 ondrej ondrej 66 May  5 23:57 aa/lib/python2.7/site-packages/matplotlib -> ../../../../opt/python/llzf/lib/python2.7/site-packages/matplotlib
```
You can see, that while `aa/lib/python2.7/site-packages/` is a regular newly created directory, the `matplotlib` is not a directory but a link. As such, what happens when you do `setup.py install` for matplotlib by hand? Will Python recreate the `matplotlib` directory? I don't think so --- it will write into the link, i.e. into our store. So this is a big problem.