PR-1021: Merge Keplin project scripting code into Kotlin core.

Overhauls the scripting layers (GenericRepl and related, and JSR223 and related)
Adds repeating modes (none, only latest eval'd line, or random order)
Also adds better thread-safe IO capturing, default imports, SimpleRepl wrapper, more unit tests

NOTE: the script-util part of the pull request was rejected due to various problems and incompatibilities.
It may be incorporated into the code later.

(originally cherry picked from commit 6f7d517)

libraries/tools/kotlin-script-util/src/test/kotlin/org/jetbrains/kotlin/script/util/ScriptUtilIT.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
+ * Copyright 2010-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.