relax scipy and numpy version requirement in requirements.txt

[graik]

pip install -r requirements.txt always insists on recompiling numpy and scipy even if they are already installed on the system. The version given in requirements.txt is higher than the default versions in Ubuntu 14.04 LT server (which is the most common server platform).

Compilation of latest scipy from pip initially failed. Needed some additional dependencies. Solution:
sudo apt-get build-dep python-scipy and then repeat the pip command.

[leasunhy]

The "blue pill" now uses the precompiled version of numpy, scipy, pillow and gevent, which will dramatically reduce the installation time :-)
Since relaxing the version constrains may break the software, we may postpone this job until the epic release of 1.0.0 version of the software 😉
Thank you!