incorporated a few unit tests -- run automatically with R CMD CHECK
fixed call to rm() in resume.default() to satisfy R CMD CHECK note -- resume.default: no visible binding for global variable ‘mod’
added examples to all exported functions to comply with CRAN
changed depends to imports and added importsFrom() to NAMESPACE for all imported functions
changed name of toy test file to comply with recommended testthat formatting
made test-all.R only run new style of testthat execution if testthat version is high enough to support -- followed devtools model
updated NAMESPACE and roxygen comments to include importFrom for all required imports