of the parameter vectors.

save_jpeg: Use TRUE instead of true

In some verisons on jpeg, TRUE is an enum, and so `true`
fails because it is not of the enum's type. Now, all the
libjpeg calls use TRUE/FALSE.

Fixes https://github.com/davisking/dlib/issues/129

learning rate.

shenanigans in a separate process.

just dlib exceptions.

Concat layer

Added getter for trainer::train_one_step_calls

dimensions of its inputs rather than always outputting a tensor that has the
dimensions of its immediate predecessors.

find_max_box_constrained().  Now the bounds can be empty for some variables.