a typedef had not to be suppressed but put in a #ifdef where used

a bad indentation corrective
avoid possible lookup of soa_iterator operators with the global boost simd overloaded operators
Merge pull request #817 from jtlap/typedef_missing

a typedef had not to be suppressed but put in a #ifdef where used
simd value must be passed by const-ref in gammaln
missing include in pow2 unit test
wrong type in condition for scalar load specialization
nt2::value is not required anymore

As tests and other systems now rely on the Sequence or
FusionSequence nature of tested elements, the need for
the nt2::value extension point is moot. This patch removes
all reference to it.
Fix incorrect type in complex mul test
Fix ULP comptaton on non fundamental types

Types like dry behave as their underlying value type but
don't get processed properly in max_ulps. This new strategy
consists to turn any unknown type into its primitive type
before computing ULP with fundamental type formula.