Merge pull request #12 from nh2/nh2fixes

A few more correctness fixes
'cabal_macros.h' is not the only one possible extra dep.
Handle 'hi_p-boot' files.
Thinko.
Unbreak the testsuite.
s/String/FilePath/.
Add a 'fatal' helper.
80-col violations.
Make -osuf and -hisuf work with .hs-boot files.
Tests for -osuf and -hisuf.
When just passing on to GHC, pass the original arguments.

We accidentally passed the custom parsed ones.

To do this, refactor `getGhcArgs` so that it first removes all
parmake options (in order to preserve the original GHC options),
and then does what it did before.
Main: Remove guessOutputFilename. The final ghc pass accounts for it