Add TriangularDist
Add doc for triangular distribution
Merge branch 'master' into triangulardist

Conflicts:
	src/Distributions.jl
Add triangular to univarites.jl
Merge d657f900aff725813b1fb23304befa1f497af1f6 into 3d661c2a9cdfd9cf2efeb7fc74a2dd017209790b
Merge commit 'bc94efaa6646fcf362614ce2788bd0e18111c0b7'