Initial checkin of klib support.

The libraries exist in two incarnations:
    packed foo.klib and unpacked foo/ .
The compiler when given '-library foo' expects to find either
a foo.klib file and unpack it, or an already unpacked foo/ directory.

The stdlib is always unpacked in dist/klib .

The semantics of -o has changed slightly.
It now accepts '-o foo' and the compiler
either produces foo.kexe or foo.klib .

runtime/build.gradle

@@ -43,6 +43,8 @@ targetList.each { targetName ->
     }
 }
 
+task hostRuntime(dependsOn: "${rootProject.ext.host}Runtime")
+
 task clean << {
     delete buildDir
 }