Pimped up the example in the README file

Example

-------

Here's a simple example to give an idea of how it works. This example

does everything from a single python interpreter for the sake of

clarity, but the actual intentention is to share arrays between

interpreters.

	import numpy as np

	import SharedArray as sa

	# Create an array in shared memory

	a = sa.create("test1", 10)

	# Attach it as a different array. Note that this could have

	# done from another python interpreter as long as it runs

	# on the same computer.

	b = sa.attach("test1")

	# See how they are actually sharing the same memory block

	a[0] = 42

	print(b[0])

	# Destroying a does not affect b.

	del a

	print(b[0])

	# See how "test1" is still present in shared memory even

	# though we destroyed the array a.

	sa.list()

	# Now destroy the array "test1" from memory.

	sa.delete("test1")

	# The array b is not affected, but once you destroy it

	# then the data are lost.

	print(b[0])

Functions

### `SharedArray.create(name, shape, dtype=float)`

This function creates an array in shared memory identified by

`name`.  The `shape` and `dtype` arguments are the same as the numpy

function `numpy.zeros()`.  The returned array is initialized to zero.

The shared memory block holding the content of the array will not be

This function creates an array in shared memory identified by `name`.

The `shape` and `dtype` arguments are the same as the numpy function

`numpy.zeros()`.  The returned array is initialized to zero.  The

shared memory block holding the content of the array will not be

deleted when this array is destroyed, either implicitly or explicitly

by calling `del`, it will simply be detached from the current process.

To delete a shared array use the `SharedArray.delete()` function.

This function returns a list of previously created shared arrays,

their name, data type and dimensions.  At the moment this function

only works on Linux and requires Python 3.

only works on Linux because it accesses files exposed under

`/dev/shm`.  There doesn't seem to be a portable method of doing that.

Requirements

------------