Step size for progress reporting via the config file

[snikumbh]

In logging messages, the user should be able to set the step size for progress reporting, i.e., how frequently the user wishes to see progress reported. For example, in the config file, the user could set a value of 10, to denote that the time-consuming functions, such as applyTransformation and computeMultiInstanceKernel, report progress in steps of 10% of the training data size.