added deprecation warning for LineModel and added note in TODO.txt

TODO.txt

@@ -8,6 +8,10 @@ Version 0.14
 * Remove deprecated ``skimage.restoration.nl_means_denoising``.
 * Remove deprecated ``skimage.filters.gaussian_filter``.
 * Remove deprecated ``skimage.filters.gabor_filter``.
+* Remove deprecated ``skimage.measure.LineModel`` and
+  add an alias LineModel = LineModelND. While the deprecated LineModel has for
+  parameters `(dist, theta)`, LineModelND has the more general parameters
+  `(origin, direction)`.
 
 
 Version 0.13

skimage/measure/fit.py

@@ -2,6 +2,7 @@ import math
 import warnings
 import numpy as np
 from scipy import optimize
+from .._shared.utils import skimage_deprecation
 
 
 def _check_data_dim(data, dim):
@@ -53,6 +54,11 @@ class LineModel(BaseModel):
 
     """
 
+    def __init__(self):
+        self.params = None
+        warnings.warn(skimage_deprecation('`LineModel` is deprecated, '
+                      'use `LineModelND` instead.'))
+
     def estimate(self, data):
         """Estimate line model from data using total least squares.