flipConfig1Dmany: Flip a single site randomly many times
Description
Given a vector of flip sites, 1s or -1s, representing up and down spins
respectively, flip any of the site randomly, repeat it many times.
The function uses default RNG (Marsienne-Twister) unless changed by the user,
within R, to generate a vector that contains 1s or -1s. This function calls
'flipConfig1Dmany' C function.