Refactor: first pass

* moved script files in their own directory
* renamed man folder to docs
* moved node files in structured directories
     i.e. node_VectorMath.py -> sverchok/nodes/vector/math.py
* renamed node_s.py to node_tree.py
* renamed util.py to data_structure.py
* most other file are now in a utils folder
* reworked the imports
    . modified the imports to point to the files new locations
    . removed the unused import
    . removed all the 'from foo import *',
      so we know what is coming from where
* reworked the import system from the main __init__.py
    . in the node modules __init__.py,
      there's a dict listing all the nodes to be imported
    . this dict is then used to import, reload,
      register and unregister nodes.
* except for being moved and the import statements modified,
  the files contents hasn't changed
Refactor: phase 2

* license block added to files
* some missed imports on the previous commit
* pep8 cleaning
* remark : update don't work
Merge branch 'refactor' into test-refactor

Conflicts:
	node_MaskJoin.py
	node_Noise.py
	node_Wireframe.py
	sverchok/data_structure.py
	sverchok/nodes/basic/viewer_bmesh.py
	sverchok/nodes/list/item.py
	sverchok/nodes/list/mask.py
	sverchok/nodes/modifier/line_connect.py
	sverchok/nodes/modifier/remove_doubles.py
	sverchok/nodes/modifier/solidify.py
	sverchok/nodes/vector/interpolation.py
	sverchok/nodes/vector/vertices_sort.py
	upgrade.py

Conflicts have been resolved
Merge pull request #229 from wclyffe/merged-refactor

New refactor branch, merged