new slice2py method is broken (cmake)

[varhub]

I noticed that new capabilities announced at #237 for Python are broken.
Slice2py has a very tricky behavior and output can't handle hierarchies.

This is due one of follow cases:
a. I don't understand how Python modules works and i'm overloading module tree
b. slice2py is very limited and not well designed

Why (b)? because _ice.py and __init__.py are decoupled and it is impossible to make a logical include tree:

• _ice.py files are "dropped" at current dir ($pwd)
• __init__.py will always placed at $pwd/module-tree/init.py
  slice2py let you tweak $pwd, but it is touched for both cases; pretty bad.

Therefore, "ease" scheme is to just place all _ice.py at root python include dir and let __init__ files the only ones with some structure.
This approach really sucks because it populate python directory with a huge number of custom slice files instead of just create a directory that contains all stuff.

• Make dirty python's dist-packages affecting usage of rest packages
• Break possibility of use same name at different tree levels
• Collateral override of other python files (from other packages) with same name
• Uninstall it will be difficult because requires to tack every file
• And so on

I almost rewrite it, but if you see the code you will cry.
BTW, it will be proposed after #280