DEPS: Drop Python 3.4 support

Closes gh-15251.

doc/source/whatsnew/v0.21.0.txt

@@ -34,7 +34,7 @@ Other Enhancements
 Backwards incompatible API changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-
+- Support has been dropped for Python 3.4 (:issue:`15251`)
 
 .. _whatsnew_0210.api:
 

pandas/compat/__init__.py

@@ -7,7 +7,7 @@
 Key items to import for 2/3 compatible code:
 * iterators: range(), map(), zip(), filter(), reduce()
 * lists: lrange(), lmap(), lzip(), lfilter()
-* unicode: u() [u"" is a syntax error in Python 3.0-3.2]
+* unicode: u() [no unicode builtin in Python 3]
 * longs: long (int in Python 3)
 * callable
 * iterable method compatibility: iteritems, iterkeys, itervalues
@@ -110,7 +110,7 @@ def signature(f):
     unichr = chr
 
     # This was introduced in Python 3.3, but we don't support
-    # Python 3.x < 3.4, so checking PY3 is safe.
+    # Python 3.x < 3.5, so checking PY3 is safe.
     FileNotFoundError = FileNotFoundError
 
     # list-producing versions of the major Python iterating functions

setup.py

@@ -246,7 +246,6 @@ def build_extensions(self):
     'Programming Language :: Python :: 2',
     'Programming Language :: Python :: 3',
     'Programming Language :: Python :: 2.7',
-    'Programming Language :: Python :: 3.4',
     'Programming Language :: Python :: 3.5',
     'Programming Language :: Python :: 3.6',
     'Programming Language :: Cython',