remove exec from makefile
Various improvments in Makefile.

* Make command silent by prefixing with @
* Add option -e to echo so as to interpret newline
* Add rules to test with python2 and python3
Clean Python code and make it compatible with both python2 and python3
Add a test with Pypy
Add a C++ version of the wordcount benchmark.

* rename C version to be more consistant
* add Makefile rules to deal with c++ version
Add a Haskell version of wordcount.

Note: it is based on lazy bytestrings and pure Map
Add a Rust version for the benchmark.
Update Julia code to encapsulate processing into a function.
Merge pull request #6 from remusao/julia

Clean Julia code