This was done to increase performance when sample exactness
is not in use. This was a consern becasue of the 2 extra function
calls each frame introduced with SA.
Enabled the use of sample exactness on gain control.
After checking the m_bbfx_leftFX.getGain() function, It was found
that this functiomn only sets a member variable, and causes no other
over head, so decided that checking if the value had changed would take more
clock cycles, than the check to see if the value had changhed.