Update for Houdini 17.5

Release 7.1.1

1. Updated for Houdini 17.5.

2. New VEX functions added:

    agentclipchannelnames
    chid
    choplocal
    choplocalt
    decode
    encode
    has_udim
    opid
    orthographic
    perspective
    prerotate
    prescale
    pretranslate
    quaterniontoeuler
    solveconstraint
    solvecurve
    solveik
    volumeindexactive

    Tip: to read about new functions quickly, copy the list in empty
    Sublime Text document, set VEX syntax and check documentation helpcards.

3. Existing VEX functions' new signatures:

    agentsolvefbik(geometry, outgeo, prim, targets, targetxforms,
                   xformgroup, iters, tolerance, pinroot)
    agentsolvefbik(geometry, outgeo, prim, targets, targetxforms,
                   xformgroup, iters, tolerance, pinroot,
                   targetweights, targetpriorities, targetdepths)
    ch(op_id, parm_index, vector_index)
    ch(op_id, parm_index, vector_index, time_in_sec)
    chf(op_id, parm_index, vector_index)
    chf(op_id, parm_index, vector_index, time_in_sec)
    chv(op_id, parm_index)
    chv(op_id, parm_index, time_in_sec)
    maketransform(xyz, angles)
    optransform(op_id)
    rotate(m, angles, xyz)
    uvdist(geometry, primgroup, uvname, uv, prim, primuv)
    uvdist(geometry, primgroup, uvname, uv, prim, primuv, maxdist)
    uvintersect(geometry, primgroup, uvname, orig, dir, pos, primuv)
    uvsample(geometry, primgroup, attr_name, uv_attr_name, uvw)