Changes in 0.4

  * New function: get_factor_scores(), calculate Bartlett factor scores
    from parameter estimates
  * summary.emEst: Added print.likelihoods argument
  * em(): Changed argument logger to verbose and set default as FALSE
  * qml(): works with non-centered exogenous variables now; fixed bug,
    max.iter does what it is supposed to do now
  * estep_lms(): fixed weird error message: "Error in
    !all.equal(rowSums(P), rep(1, nrow(P))) : invalid argument type"

Changes in 0.3

  * New function: qml(), estimate single-class model with QML as an
    alternative to LMS
  * specify_sem(): model with num.classes = 1 will be of class
    'singleClass' now instead of 'lms'
  * Data set: jordan, PISA 2006 jordan sample
  * em(): Changed logger output for NSEMM models so readability is higher;
    added max.lms = 1 so EM for single groups will only iterate once

Changes in 0.2

  * specify_sem(): changed default for interaction to "none"; fixed bug so
    psi can be set to a fixed value now; changed default constraints
  * summary.emEst(): added weights to print method
  * em(): added error message when more than one eta is specified; put
    logger = TRUE as default

