Change the wrong variable name from uniform_window to window

[kartikmandar]

The first create_window object that is the uniform window was given the variable name window. However afterwards, the code tried to call it by the name uniform_window. So I changed that uniform_window to window in : A = fft(window,nfft ) / (len(window)/2.0)

Now the code doesn't give any errors. The variable name was not instead corrected to uniform_window to maintain consistency like in all other create_window objects examples.

[matteobachetti]

@kartikmandar this is already done in #84

[kartikmandar]

Sure I didnt see it.