smten tool fails if .hi files are in the wrong place

[ruhler]

For example:

1. compile Foo.hs using smten in a subdirectory called dir.
   This produces Foo.hi in the same directory as Foo.hs, and Smten/Compiled/Foo.hs in the subdirectory dir.
2. compile Foo.hs again using smten in a subdirectory called dir2. This fails.

It fails because ghc sees Foo.hi and thinks it doesn't have to compile Foo.hs again, but it can't find Smten/Compiled/Foo.hs, because it's in a different directory.

Possible fix: the smten tool should automatically put the .hi files from stage 1in the same place as the Smten dir.