provide bounded constraints-imposing functions

[mmckerns]

provide bounded constraints-imposing functions

for example, imposing a "bounded_mean" would impose a mean, and simultaneously not violate bounds constraints.

[mmckerns]

several examples can be found in the OUQ seismic code

from seismic import bounded_mean
from seismic import soft_bounded_mean
from seismic import bounded_norm
from seismic import bounded_square_norm

[mmckerns]

added decorators for imposing bounds in r598 (as noted in ticket #182)

[mmckerns]

need to merge into trunk, but otherwise, close as worksforme.

[mmckerns]

doesn't seem to have been merged into trunk. should be open till that happens