Make a valid effort vector
Details
A valid effort vector is a named vector with one effort value for each gear. However you can also supply the effort value in different ways:
a scalar, which is then replicated for each gear
an unnamed vector, which is then assumed to be in the same order as the gears in the params object
a named vector in which the gear names have a different order than in the params object. This is then sorted correctly.
a named vector which only supplies values for some of the gears. The effort for the other gears is then set to the default effort returned by
validEffortVector(), which depends on the defaults edition.
These conversions are done by the function validEffortVector().
An effort argument will lead to an error if it is either
unnamed and of the wrong length
named but where some names do not match any of the gears
not numeric