removed some deprecation warnings from mlab

svn path=/branches/v0_98_5_maint/; revision=7107

Author: jdh2358

lib/matplotlib/mlab.py

@@ -272,11 +272,6 @@ def _spectral_helper(x, y, NFFT=256, Fs=2, detrend=detrend_none,
         pad_to = NFFT
 
     if scale_by_freq is None:
-        warnings.warn("psd, csd, and specgram have changed to scale their "
-            "densities by the sampling frequency for better MatLab "
-            "compatibility. You can pass scale_by_freq=False to disable "
-            "this behavior.  Also, one-sided densities are scaled by a "
-            "factor of 2.")
         scale_by_freq = True
 
     # For real x, ignore the negative frequencies unless told otherwise
@@ -1880,8 +1875,6 @@ def identity(n, rank=2, dtype='l', typecode=None):
     much faster.
     """
     if typecode is not None:
-        warnings.warn("Use dtype kwarg instead of typecode",
-                       DeprecationWarning)
         dtype = typecode
     iden = np.zeros((n,)*rank, dtype)
     for i in range(n):