FFT fails on Signal2Ds

[thomasaarholt]

As the title says. Terminal returns the following error:

s = hs.signals.Signal2D(sc.misc.face()).as_signal2D((2,0)).inav[0]
s.plot()
# Call the FFT function from the menu

Error:

Traceback (most recent call last):
  File "/Users/thomas/Dropbox/0_Git/hyperspyUI/hyperspyui/plugins/fft.py", line 167, in fft
    for i in do_ffts():
  File "/Users/thomas/Dropbox/0_Git/hyperspyUI/hyperspyui/plugins/fft.py", line 149, in do_ffts
    if u.endswith('-1'):
AttributeError: '_Undefined' object has no attribute 'endswith'

[vidartf]

Duplicate of #95.

[thomasaarholt]

Sorry, should have searched. Thought I was up to date on the issues.