Attempt at modularising resolvent analysis

resolventSVD.m: computes the resolvent and carries out singular value
decomposition

pipeCoords.m: computes chebyshev collocation grid, integration weights,
difference matrices etc.,

pipeOperators.m: computers the Navier-Stokes linear operator

pipeBC.m : implements either the no-slip boundary condition at the wall,
or a basic version of opposition control.

---- Modification ----
pipeVel.m : now loads turbulent velocity profiles in
allProfilesLogInterp.txt.  In addition to the superpipe data (McKeon et
al., 2004), this new files includes DNS data (Wu & Moin, 2008)