Spectral Python 0.18

Changes

• Improved handling of ENVI header files:
  • If "header offset" is missing, assume the offset is 0.
  • Stricter check for "ENVI" in the first line of the file.
  • [Issue #42] More-informative exceptions are raised when a problem is
    encountered while reading and ENVI header.
  • [Issue #46] No longer defaulting band_quantity to "Wavelength".

Bug Fixes

• [Issue #38 and #39] The tostring method has been deprecated in newer
  versions of PIL/Pillow. Using tobytes now and falling back to tostring
  if it fails.
• [Issue #40] An exception was raised when trying to get a pixel's row/col
  by CTRL-SHIFT-clicking in the ND window display.
• [Issue #44] Matplotlib was being set to interactive mode even if no SPy
  windows were displayed. This would affect behavior of other code using
  Matplotlib. Interactive mode is now set only once the first display is
  requested.
• [Issue #49] GaussianClassifier and MahalanobisDistanceClassifier method
  classify_image was failing when applied to an object that was not a
  numpy.ndarray (e.g., a SpyFile or TransformedImage).