Replace *Escape with *EscapeList

Follow the change to blueprint to make *Escape take and return a string
and add *EscapeList that take and return slices of strings.  Fix up
a few places that were unnecessarily converting a string to a slice
and back to a string.

Test: m nothing
Change-Id: I3fa87de175522205f36544ef76aa2f04aef1b936
diff --git a/java/aar.go b/java/aar.go
index 9eb2b27..c30632e 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -168,7 +168,7 @@
 		} else {
 			versionName = ctx.Config().AppsDefaultVersionName()
 		}
-		versionName = proptools.NinjaEscape([]string{versionName})[0]
+		versionName = proptools.NinjaEscape(versionName)
 		linkFlags = append(linkFlags, "--version-name ", versionName)
 	}