Revert "[ lib-succeed ] Ignoring Agda interface files"

This reverts commit 554d09d42bef6673db38ff4a83ef46a4ff7d3ab5.
[ lib-succeed ] Removing Agda interface files
Merge branch 'maint-2.4.2'
[ issue 1283 ] Added type signatures
[ Utils.List ] Renamed mhead and mlast to headMay and lastMay

I took the names from the safe library (see
http://hackage.haskell.org/package/safe).
[ Utils.List ] Add headDef function.

From the safe library (see http://hackage.haskell.org/package/safe).
Merge branch 'maint-2.4.2'
[ cosmetics ] CamelCase in Common.Reflection tests.
[ issue 1304 ] Fixed by adding the missing Eq instance
Merge branch 'maint-2.4.2'
newtype for CPUTime in Agda.Utils.Time
Measure time for give command (with -v profile.interactive:10)
MIN_VERSION macros expect only three arguments when doing make tags
newtype for CPUTime in Agda.Utils.Time
MIN_VERSION macros expect only three arguments when doing make tags
Merge branch 'maint-2.4.2'
[ Issue 1283 ] Added missing type signatures in Concrete.Pretty.
Merge branch 'maint-2.4.2'
[ bug fix ] unquoteDecl is not allowed in mutual

should not cause __IMPOSSIBLE__ though
Merge branch 'maint-2.4.2' of github.com:agda/agda into maint-2.4.2