temp CI bug fix: no 3.5; use old Pandas

See Issue #27 for details.
I am using other branches to find a better solution.

.travis.yml

@@ -2,7 +2,8 @@
 language: python
 python:
   - "3.4"
-  - "3.5"
+  # Temp bugfix: I don't know why 3.5 is erroring. See Issue #27 https://github.com/mroberge/hydrofunctions/issues/27
+  #- "3.5"
   - "3.6"
 
 install:
@@ -22,7 +23,8 @@ install:
 
   # the "--only-binary" option was added in pip 7 back in 2015; still to be safe
   - pip install --upgrade pip setuptools wheel
-  - pip install --only-binary=numpy,scipy,pandas,Ipython numpy scipy pandas ipython
+  # Temp bugfix: don't allow latest version of Pandas0.23.0 I don't know why this works.
+  - pip install --only-binary=numpy,scipy,pandas,Ipython numpy scipy pandas!=0.23.0 ipython
 
   # Install codecov so I can use it (and coverage.py) to run setup.py
   # However, keep codecov in setup.py so that it gets installed for local usage too.