Remove incompatibility with mpl v3.x

In mpl v3.x, cbook.is_scalar has been removed.  It is used in only
one place in basemap, and in that location it is not actually doing
anything useful.

I made a small reorganization and cleanup in that location in the
interp function to fix another bug in which masked locations were
being inadvertently unmasked without being filled with the mask
value specified in the kwarg.

Author: efiring

lib/mpl_toolkits/basemap/__init__.py

@@ -14,7 +14,7 @@
 """
 from distutils.version import LooseVersion
 from matplotlib import __version__ as _matplotlib_version
-from matplotlib.cbook import is_scalar, dedent
+from matplotlib.cbook import dedent
 # check to make sure matplotlib is not too old.
 _matplotlib_version = LooseVersion(_matplotlib_version)
 _mpl_required_version = LooseVersion('0.98')
@@ -4984,12 +4984,11 @@ def interp(datain,xin,yin,xout,yout,checkbounds=False,masked=False,order=1):
         dataout = map_coordinates(datain,coords,order=3,mode='nearest')
     else:
         raise ValueError('order keyword must be 0, 1 or 3')
-    if masked and isinstance(masked,bool):
-        dataout = ma.masked_array(dataout)
+    if masked:
         newmask = ma.mask_or(ma.getmask(dataout), xymask)
-        dataout = ma.masked_array(dataout,mask=newmask)
-    elif masked and is_scalar(masked):
-        dataout = np.where(xymask,masked,dataout)
+        dataout = ma.masked_array(dataout, mask=newmask)
+        if not isinstance(masked, bool):
+            dataout = dataout.filled(masked)
     return dataout
 
 def shiftgrid(lon0,datain,lonsin,start=True,cyclic=360.0):