branch: iss1 RuntimeError: Image view dimensions out of range for data

here is my program:

```
import sys
import string

from gamera.core import *
from gamera.toolkits import staffline_removal
from gamera.toolkits import lyric_extraction

init_gamera()

def print_image_data(self):
print "stride", self.data.stride
print "ncols", self.data.ncols
print "nrows", self.data.nrows
# print "dim", self.data.dim
print "page_offset_x", self.data.page_offset_x
print "page_offset_y", self.data.page_offset_y
# print "offset", self.data.offset
print "size", self.data.size

# Load image from command line
image = load_image(sys.argv[1])

print "image data after load"
print type(image)
print_image_data(image)

# Binarize image
onebit = image.djvu_threshold()

print "image data after binarization"
print type(onebit)
print_image_data(onebit)

# get an estimation of staff height
sh = onebit.staffheight_estimation()
# staffspace
ss = onebit.staffspace_estimation()
# do lyric line detection
llmask = onebit.baseline_detection(ss) #<--- the problem happens here
print 'Staff-height estimation', sh,'Staff-space estimation', ss

# outputfile path
if '.' in sys.argv[1]:
fpath = string.join(sys.argv[1].split('.')[0:-1],'.')+"_llmask.png"
else:
fpath = sys.argv[1]+"_llmask.png"

llmask.save_PNG(fpath)
```
#### end program

here is the output of the program

```
image data after load

stride 2712
ncols 2712
nrows 3368
page_offset_x 0
page_offset_y 0
size 9134016
image data after binarization

stride 2712
ncols 2712
nrows 3368
page_offset_x 0
page_offset_y 0
size 9134016
staffspace:36, staffheight:4
staffspace:36, staffheight:4
Traceback (most recent call last):
File "./lyric-baseline-study.py", line 40, in
llmask = onebit.baseline_detection(ss)
File "/Users/nickesterer/Documents/development/gamera_env/lib/python2.7/site-packages/gamera/toolkits/lyric_extraction/plugins/lyricline.py", line 93, in __call__
valid_angle_degree, scalar_valid_height, valid_min_group)
RuntimeError: Image view dimensions out of range for data
nrows 27
offset_y 3342
data nrows 3368
data offset_y 0
ncols 37
offset_x 66
data ncols 2712
data offset_x 0
```

This was happening before installing the most recent commit to DDMAL/document-preprocessing-toolkit, but only on some images and not on others. Now using the same images as before, it happens on all images.