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 .

common/build.gradle

@@ -27,7 +27,7 @@ targetList.each { targetName ->
 }
 
 task build {
-    dependsOn hostHash
+    dependsOn "${host}Hash"
 }
 
 task clean << {