rewrote tests for RandomGov constructor to explicitly test specific methods.
replaced test-randomGov with test-RandomGov-constructor.
removed test related to extractRelevantColumns in test-predictRandomGov.
fixed performComWidePrediction_c to handle case where training data is a vector.
cleaned up test-buildRandomGov to get rid of checkEstParams_x functions -- that functionality is now tested for in constructors.
started adding internal roxygen documentation for internals of buildRandomGov.
refactored RandomGov constructor to consider numeric, factor, and formula arguments.
updated package documentation.