travis python2.7 is failing because of ipython dependency
Looks like ipython 6 dropped python2 support and travis does not like to install something else:
```
Collecting ipython>=5.0.0 (from androguard==2.0)

  Downloading ipython-6.0.0.tar.gz (5.1MB)

    100% |################################| 5.1MB 108kB/s 

    IPython 6.0+ does not support Python 2.6, 2.7, 3.0, 3.1, or 3.2.

    When using Python 2.7, please install IPython 5.x LTS Long Term Support version.

    Beginning with IPython 6.0, Python 3.3 and above is required.

    See IPython `README.rst` file for more information:

        https://github.com/ipython/ipython/blob/master/README.rst

    Python sys.version_info(major=2, minor=7, micro=9, releaselevel='final', serial=0) detected.

    Your pip version is out of date, please install pip >= 9.0.1. pip 6.0.7 detected.

    Complete output from command python setup.py egg_info:

    

    

    IPython 6.0+ does not support Python 2.6, 2.7, 3.0, 3.1, or 3.2.

    

    When using Python 2.7, please install IPython 5.x LTS Long Term Support version.

    

    Beginning with IPython 6.0, Python 3.3 and above is required.

    

    

    

    See IPython `README.rst` file for more information:

    

    

    

        https://github.com/ipython/ipython/blob/master/README.rst

    

    

    

    Python sys.version_info(major=2, minor=7, micro=9, releaselevel='final', serial=0) detected.

    

    Your pip version is out of date, please install pip >= 9.0.1. pip 6.0.7 detected.

    

    

    

    ----------------------------------------

    Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-WRMWjs/ipython

The command "pip install ." failed and exited with 1 during .

```

Who has travis$foo and can fix this?
diff --git a/setup.py b/setup.py
index 3a12591b..56b7ca67 100644
--- a/setup.py
+++ b/setup.py
@@ -4,6 +4,11 @@ import os
 
 from setuptools import setup, find_packages
 
+if sys.version_info >= (3,):
+    install_requires = ['pyasn1', 'cryptography>=1.0', 'future', 'ipython>=5.0.0', 'networkx', 'pygments']
+else:
+    install_requires = ['pyasn1', 'cryptography>=1.0', 'future', 'ipython>=5.0.0,<6', 'networkx', 'pygments'],
+
 # TODO this is actually a hack... How to copy the files to the right folder?
 #guidir = os.path.join(sys.prefix, 'Scripts', 'androguard', 'gui')
 #if not os.path.isdir(guidir):
@@ -19,7 +24,7 @@ setup(
              'androlyze.py',
              'androdd.py',
              'androgui.py',],
-    install_requires=['pyasn1', 'cryptography>=1.0', 'future', 'ipython>=5.0.0', 'networkx', 'pygments'],
+    install_requires=install_requires,
     extras_require={
         'GUI': ["pyperclip", "PyQt5"],
         'docs': ['sphinx', 'sphinxcontrib-programoutput'],
@@ -28,5 +33,5 @@ setup(
         'graphing': ['pydot'],
     },
     setup_requires=['setuptools'],
-    
+
 )
['setup.py']