testgen: kompile: renamed option "concrete-sort" to "test-gen" and updated option description
testgen: assigned each heating/cooling rule a automatically generated label during komilation
kompile: allowed heating/cooling rules to heat/cool more than one variable when kompiling for test generation
kompile: minor: renamed the labels assigned to heating/cooling rules when kompiling for test generation
testgen: refactored some code for checking the depths of nested constructs
testgen: tuned the parameters a little bit
testgen: only performed pgm concretization when two-phase generation strategy is used
testgen: implemented a round-robin style state selection strategy
testgen: a bunch of changes to code related to test generation in SymbolicRewriter
testgen: included my version of imp.k for test generation; very messy