Added function to compute analytic representation of a real signal (DSP.Util.hilbert)
Exported hilbert function
Use FFTW plan interface

By my calculations, this is about twice as fast
Tweak some tests

Fix typos and add checks for odd numbers of samples and integer
arguments
Merge pull request #16 from jfsantos/hilbert

Added hilbert to the util module (computes the analytic signal from a real signal).
Added documentation for the hilbert function
Fix lexlt function

Not sure how this worked before, since it was obviously wrong. Maybe
I was just lucky?
Avoid "imported binding for eps overwritten in module Main" warning

I am not convinced there was anything wrong with this code, but in any
case this avoids the warning.
Revert "Avoid "imported binding for eps overwritten in module Main" warning"

This reverts commit 1318cd6d21234069499b7d282ee51673716b14f2.
Fix real cause of eps warning (this variable wasn't used anyway)
Fixes #20