ctr: null
  resolution (width,height,depth) =  0 0 1
  origin (x,y,z) =  0 0 0
  full res =  0 0 0
  full origin =  0 0 0
  untiled
  format =  unknown
  nchannels =  0
  channelformats =  ()
  channel names =  ()
  alpha channel =  -1
  z channel =  -1
  deep =  False

ctr: UINT16
  resolution (width,height,depth) =  0 0 1
  origin (x,y,z) =  0 0 0
  full res =  0 0 0
  full origin =  0 0 0
  untiled
  format =  uint16
  nchannels =  0
  channelformats =  ()
  channel names =  ()
  alpha channel =  -1
  z channel =  -1
  deep =  False

ctr: 640x480,3 UINT8
  resolution (width,height,depth) =  640 480 1
  origin (x,y,z) =  0 0 0
  full res =  640 480 1
  full origin =  0 0 0
  untiled
  format =  uint8
  nchannels =  3
  channelformats =  ()
  channel names =  ('R', 'G', 'B')
  alpha channel =  -1
  z channel =  -1
  deep =  False

lots of fields
  resolution (width,height,depth) =  640 480 1
  origin (x,y,z) =  1 2 3
  full res =  1280 960 7
  full origin =  4 5 6
  tile size =  32 64 16
  format =  float
  nchannels =  5
  channelformats =  (2, 2, 2, 2, 11)
  channel names =  ('R', 'G', 'B', 'A', 'channel4')
  alpha channel =  3
  z channel =  -1
  deep =  False

channel bytes = 4
  channel_bytes(1) = 4 native 1
  channel_bytes(4) = 4 native 4
pixel bytes = 20 native 8
scanline bytes = 12800 native 5120
tile bytes = 655360 native 262144
image bytes = 6144000 native 2457600
tile pixels = 32768
image_pixels = 307200
size_t_safe = True

get_int_attribute('foo_int') retrieves 14
get_int_attribute('foo_int',21) with default retrieves 14
get_int_attribute('foo_no',23) retrieves 23
get_float_attribute('foo_float') retrieves 3.1400001049
get_float_attribute('foo_float_no') retrieves 0.0
get_float_attribute('foo_float_no',2.7) retrieves 2.70000004768
get_string_attribute('foo_str') retrieves blah
get_string_attribute('foo_str_no') retrieves 
get_string_attribute('foo_str_no','xx') retrieves xx

get_attribute('foo_int') retrieves 14
get_attribute('foo_float') retrieves 3.1400001049
get_attribute('foo_str') retrieves blah
get_attribute('foo_vector') retrieves (1.0, 0.0, 11.0)
get_attribute('foo_matrix') retrieves (1.0, 0.0, 0.0, 0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1.0, 2.0, 3.0, 1.0)
get_attribute('foo_no') retrieves None

extra_attribs size is 5
0 foo_str string blah
"blah"
1 foo_int int 14
14
2 foo_float float 3.1400001049
3.14
3 foo_vector vector (1.0, 0.0, 11.0)
1 0 11
4 foo_matrix matrix (1.0, 0.0, 0.0, 0.0, 0.0, 2.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1.0, 2.0, 3.0, 1.0)
1 0 0 0 0 2 0 0 0 0 1 0 1 2 3 1

Done.
