'**SUMMARY**
This method returns an image of the blob\'s mask. Areas where the blob are present are white
while all other areas are black. The image is cropped to match the blob area.
**RETURNS**
Returns a SimplecV image of the blob\'s mask, cropped to fit.
**EXAMPLE**
>>> img = Image("lenna")
>>> blobs = img.findBlobs()
>>> blobs[-1].blobMask().show()'

def blobMask(self):

    return self.mMask
