Removing ind2sub and sub2ind calls
Implemented sub2ind matlab function
Implemented meshgrid Matlab function
Implemented ndgrid Matlab function
Implemented randi Matlab function
Implemented rng Matlab function
Implemented ind2sub Matlab function
Update unifrnd and normrnd test values

New seed/generator fixed values modified the values to
be checked. Also normrnd Kolmogorov's test had cases
of false positive that were fixed by fixing the seed.
Move class_ and numeric class objects into generative
Setup generative functions documentation
Matlab Inf is nt2::inf not nt2::infs
Matlab NaN is nt2::nan not nt2::nans
Add alias for writing matlab like size in documentation
Documentation for constant generators
Various cosmetic fixes in generative

 - constant_ result_type have been renamed to base_type
 - use explicit splat whenever possible
 - use if_else_zero whenever possible
 - factorized some constants helpers