Added some notes. Set up the BE repository.
Changed reference interval to be [0, 1]
Implemented quadrature of logarithmic singularities.
Implemented QuadGaussOneOverR quadrature method based on Piessens(1970)
    -- also some simple tests of the quadrature methods.
Added elastostatic kernels. Direct source is the book on
boundaryelements.com, but the kernels match with what I see elsewhere,
including Crouch, Starfield.