Drop pymongo dev tests to speed things up.

We don't need to test it before a stable release and removing it shaves off
considerable amount of time from Travis builds.

.travis.yml

@@ -15,7 +15,6 @@ env:
 - PYMONGO=2.7
 - PYMONGO=2.8
 - PYMONGO=3.0
-- PYMONGO=dev
 
 matrix:
   fast_finish: true
@@ -94,5 +93,5 @@ deploy:
   on:
     tags: true
     repo: MongoEngine/mongoengine
-    condition: "$PYMONGO = dev"
+    condition: "$PYMONGO = 3.0"
     python: 2.7

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = {py27,py33,py34,py35,pypy,pypy3}-{mg27,mg28,mg30,mgdev},flake8
+envlist = {py27,py33,py34,py35,pypy,pypy3}-{mg27,mg28,mg30},flake8
 
 [testenv]
 commands =
@@ -9,7 +9,6 @@ deps =
     mg27: PyMongo<2.8
     mg28: PyMongo>=2.8,<3.0
     mg30: PyMongo>=3.0
-    mgdev: https://github.com/mongodb/mongo-python-driver/tarball/master
 setenv =
     PYTHON_EGG_CACHE = {envdir}/python-eggs