Rewrite tests that got disabled by constant folding

Some tests become useless once constant folding has bee used. A few
bugfixes were found while disabling the optimization, I add them here
with a test case that prevents constant folding.
Fix bad runas for benchmark
Merge pull request #198 from pbrunet/bench_fix

Fix bad runas for benchmark
Add scrabble test case
Add exception support in Boost initialisation only if needed

* Avoid extra loading overhead
Remove clang Warning
Lazy evaluation of single assigned numpy expression
Add good code for lazy analysis
Add log to numpy
Specialize bitwise nan operation for boolean
Lazy typing for conditional statements
Add documentation for Lazyness analysis
Merge pull request #199 from pbrunet/add_test_case

Add scrabble test case
Merge pull request #178 from pbrunet/lazy

Lazy
Merge pull request #194 from serge-sans-paille/more-test-cases

Rewrite tests that got disabled by constant folding
Fix setup sdist

It appears that the source distribution did not bundle nt2 or
boost.simd, so the package on pypi was faulty.
Merge pull request #203 from serge-sans-paille/fix-setup

Fix setup sdist
Check pep8 using pytest-pep8 extension from pip

* Fix pep8 check as some pep8 constraints where not checked
Merge pull request #201 from pbrunet/pep8

Check pep8 using pytest-pep8 extension from pip
Fix missing declaration for zeros_like implementation with boost.simd