Quicknet - Enable Learning Partial Weights

As in the original Quicknet_v3_20, the parameter mlp_lrmultiplier can scale the learning rate per-section. If the value is set to 0.0, then that section weight will not be updated. However, only it does not provide full freedom to set any section to be kept during training. As the values after the first non-zero value will be non zeros.

To remove this restrict, following steps need to be done:
In QN_MLP_BunchFlVar.cc:
QN_MLP_BunchFlVar::train_bunch() function:
about line 427:
if (cur_layer!=nlayers-1 && backprop_weights[cur_weinum+1])

ToDo: remove "&& backprop_weights[cur_weinum+1]"

In QN_MLP_BaseFl.cc
QN_MLP_BaseFl::set_learnrate() function:
about line 334:
else
     break;

ToDo: remove these two sentences.

The workable sourcecode, at least works for my purpose, can be found here: https://www.comp.nus.edu.sg/~li-bo/src/quicknet_linAF.tar