[Tetuhi-vgs] Some fixes for x86_64

[Eric Piel]

Hi,

This is a quick message to summarize what I needed to change (against 
the git tree) to run tetuhi on my x86_64 machine:
* Compilation must be done with -fPIC. This implies not only changing 
the COMMON_OPTS variables, but also running "python setup.py build_ext" 
with "CFLAGS=-fPIC LDFLAGS=-fPIC"
* "pyserf_helpers.c" is not found in nnpy.c, it must be changed to 
../lib/pyserf_helpers.c
* The main difficulty: collect_entropy() of vg/cblobdetect.py should 
return a list of integers, not of longs (otherwise, overflows appear) so 
line 315 should be:     return list(array.array("i", e2))

The last two points could probably be directly fixed in the source, as 
described.

Hoping it helps some people :-)
See you,
Eric