add findFile :: [FilePath] -> String -> IO (Maybe FilePath) (see #6094)

Just an export of part of the implementation of findExecutable, which
is useful for people wanting to do their own findExecutable using
something other than the current PATH.
fix comment mistake
remove type signatures in comments, they bitrot (#6142)
Follow changes in base
Update tests following changes in base
Bump version to 1.1.1.0
Update dependencies.
Bump version to 1.2.0.0 (#7144)
Fix build for base < 4.6

Build on 7.0.3 and up. Maybe lower.
Add comment to .cabal file saying what GHC 7.6.1 shipped with
Bump version number following new policy

We now keep the HEAD version numbers as values which would be suitable
for immediate release.
Update dependencies
Bump base lower version to 4.5 (the version GHC 7.4.1 came with)
Remove code for old, unsupported versions of GHC
Fix Haddock markup
Make getModificationTime return a hi-resolution time; fixes #7473

We were only getting an integral number of seconds before. This change
only affects non-Windows platforms. Patch from Duncan Coutts.
T4113 is broken in OS X (#7604)
Fix 'createDirectoryIfMissing _ "."' in c:\ on Windows

We were getting a
    CreateDirectory ".": permission denied (Access is denied.)
exception, so now we treat isPermissionError like isAlreadyExistsError
when creating directory (that is, if there is a directory with that
name then we ignore the exception).
Fix T4113 on OS X x86_64
Follow testsuite changes