Explicitly initialize energy in eMUnpairedRegion

The eMUnpairedRegion() method of RNAScoring does not initialize the value of `energy`. There is a path through the conditionals in this method where `energy` is never set (the case when `j1+1<i2-1` and `D2MODE=0`)—and this path is in fact used in the code! Thus, it is possible for an essentially random value of `energy` to make it out. I don't know enough about the science to say what the correct value of `energy` is in this case, so this patch just initializes `energy` to 0.