setup.py: Add work around for installing pandas

For some reason the automatic install of pandas will fail compilation
due to numpy. A workaround for this issue is to specify numpy in
`setup_requires` as mentioned in
numpy/numpy#2434

setup.py

@@ -70,6 +70,9 @@
     license='Apache v2',
     maintainer='ARM Architecture & Technology Device Lab',
     maintainer_email='workload-automation@arm.com',
+    setup_requires=[
+        'numpy'
+    ],
     install_requires=[
         'python-dateutil',  # converting between UTC and local time.
         'pexpect>=3.3',  # Send/receive to/from device
@@ -79,7 +82,7 @@
         'requests',  # Fetch assets over HTTP
         'devlib',  # Interacting with devices
         'louie',  # callbacks dispatch
-        'wrapt',  # better decorators 
+        'wrapt',  # better decorators
         'pandas>=0.13.1',  # Data analysis and manipulation
     ],
     extras_require={