cleanup methods exposed by cbt #385
Description
right now this list can be fairly long, even for a simple build
$ cbt <tab>
_context context finalBuild moduleKey runClass taskCache
c crossScalaVersionsArray flatClassLoader name scalacOptions taskNames
classLoader defaultScalaVersion generatedSources needsUpdateCompat scaladoc test
classLoaderCache dependencies help nonEmptySourceFiles scalaMajorVersion toString
classpath dependenciesArray jarTarget projectDirectory scalaTarget transientCache
clean dependencyClasspath lastModified publish scalaVersion transitiveDependencies
cleanFiles dependencyClasspathArray lib r show triggerLoopFiles
compile dependencyTree libraries recursive sourceFiles triggerLoopFilesArray
compileClasspath docTarget localJars repl sources void
compileDependencies enableConcurrency logEmptySourceDirectories resourceClasspath t zincVersion
compileStatusFile exportedClasspath logger rt target
compileTarget exportedClasspathArray mainClasses run targetClasspat