travis ci: add erlang 17.1 to the build matrix
examples: add a page rank example
Merge pull request #576 from pooya/page

examples: add a page rank example
examples: add a mapreduce solution for travelling salesman problem
Merge pull request #578 from pooya/tsp

examples: add a mapreduce solution for travelling salesman problem
examples: add ipython example
readme: add ipython screenshot
Merge pull request #581 from pooya/ipython

Ipython
readme: fix the path to the ipython example
readme: add links to disco wiki pages
doc: fix the release date of disco 0.5.3
update readme
update the ipython example
cloud: Add setup scripts for google cloud
cloud: add some documentation to google cloud scripts
Merge pull request #582 from pooya/google

Add scripts to automate deployment on google cloud
settings: Set the number of workers to the number of CPUs by default
Merge pull request #583 from pooya/ncpus

settings: Set the number of workers to the number of CPUs by default
classic worker: never try to save the results in ddfs in the python client
worker: delete the code about saving the results of the last stage into ddfs