Better matching for Dict
Better matching for set
Fix documentation
Repeat optimisation until nothing change.
Avoid long compilation time for set/dict pattern
Fix around implementation

It is only possible to have a numexpr for floating point expressions.
Merge pull request #318 from pbrunet/pattern_unordered

Pattern unordered
Merge pull request #327 from serge-sans-paille/fix-around

Fix around implementation
Disable OpenMP support if libgomp is not found