Moved python code to tools/, now gets installed

In order to remove more environment variable usage, the tinyos python
code must be installed on the user's system instead of in the tinyos
tree. This commit moves all the python to tools so automake will install
it. Doing this requires one subtle change: "import tos" will no longer
work. It needs to be "from tinyos import tos" now.

I think I updated all of the relevant files.

One note: python3 is handled a bit weirdly, and therefore tos-serlook.py
may not be able to find tinyos.misc.hexdump. It seems that
/usr/local/lib/python3/dist-packages is not in the search path by
default. I fixed this by adding "tinyos.pth" containing the correct
directory to /usr/local/lib/python3.2/dist-packages.