Cache blocking vnl bra
Optimization: Cache blocking for the routine vnl_mat_bra. On a test calculation this lead to a boost of ~35%. This is confirmed by a significamt reduction of caches misses using cachegrind.
Optimization of the application of the pseudopotential in some cases.
- I have checked that my code follows the Octopus coding standards
- I have added tests for all the new features added in this request.