1. make tuneinit into prior
2. (important) update the whole parameter vector together
add method 'DP' as default. also 'scale' for scaled normal mixture
Merge branch 'bayessinglewhole' into mixture-whole
1. correct prior to be sigmaa instead of sigmaa/2
2. disenable tunning
1.allow methods for single normal bays.
2. method: 'whole' default; 'element'
allow sampling method 'whole' (default) and 'element' (block gibbs)