Implement workaround for matplotlib 1.4.2 bug

This is an unpleasant hack, but this is also a nasty bug and matplotlib
apparently won't be releasing a fix for a few months:
matplotlib/matplotlib#3699

This closes #344

doc/releases/v0.5.1.txt

@@ -0,0 +1,6 @@
+
+v0.5.1 (Unreleased)
+-------------------
+
+- Implemented a workaround for a bug in matplotlib 1.4.2 that prevented point markers from being drawn when the seaborn styles had been set. See this `github issue <https://github.com/mwaskom/seaborn/issues/344>`_ for more information.
+

seaborn/rcmod.py

@@ -389,6 +389,13 @@ def plotting_context(context=None, font_scale=1, rc=None):
         font_dict = {k: context_dict[k] * font_scale for k in font_keys}
         context_dict.update(font_dict)
 
+    # Implement hack workaround for matplotlib bug
+    # See https://github.com/mwaskom/seaborn/issues/344
+    # There is a bug in matplotlib 1.4.2 that makes points invisible when
+    # they don't have an edgewidth. It will supposedly be fixed in 1.4.3.
+    if mpl.__version__ == "1.4.2":
+        context_dict["lines.markeredgewidth"] = 0.01
+
     # Override these settings with the provided rc dictionary
     if rc is not None:
         rc = {k: v for k, v in rc.items() if k in _context_keys}

seaborn/tests/test_linearmodels.py

@@ -7,6 +7,7 @@
 import numpy.testing as npt
 import pandas.util.testing as pdt
 from numpy.testing.decorators import skipif
+from nose import SkipTest
 
 try:
     import statsmodels.api as sm
@@ -943,6 +944,9 @@ def test_lmplot_markers(self):
 
     def test_lmplot_marker_linewidths(self):
 
+        if mpl.__version__ == "1.4.2":
+            raise SkipTest
+
         g = lm.lmplot("x", "y", data=self.df, hue="h",
                       fit_reg=False, markers=["o", "+"])
         c = g.axes[0, 0].collections