ENH: Enhanced the problem set building on the image handing and arrays.
Illustrated dtypes, casting and their importance along with an example
using RGBA images. Also introduce edge detection.
def linspace(a, b, N):
lns = []
step = (float(b) - float(a)) / float(N - 1)
print step
for i in range(N):
lns.append(a + i*step)
return lns
print linspace(0, 5, 11)