[ Issue 1353 ] Test case (works on maint).
[ Issue 1350 ] Fixed haddocumentation and added tests of cluster functions.
Merge branch 'maint-2.4.2'
[ Issue 1353 ] Test is broken on master (probably due to sharing bug).

* Agda normalizes too far in goal display.
* De Bruijn bug leads to unjustified error message.
Fixed typos
[ issue 1283 ] Added missing type signatures
[ issue 1283 ] Fixed

* Added -fwarn-missing-signatures to Agda.cabal
* Removed {-# OPTIONS -fwarn-missing-signatures #-} from the modules.
Merge branch 'maint-2.4.2'

Conflicts:
	src/full/Agda/Utils/Pointer.hs
	src/full/Agda/Utils/Time.hs
[ .ghci ] Added -fwarn-missing-signatures
[ refactor] Using `otherwise` guard instead of pattern matching

Style teacher and me agree on using

  f pattern
    | predicate1 = foo1
    | predicate2 = foo2
    | ...
    | predicateN = fooN
    | otherwise  = bar

instead of

  f pattern
    | predicate1 = foo1
    | predicate2 = foo2
    | ...
    | predicateN = fooN

  f pattern = bar
[ LaTeX-mode] agda.sty tweak: make mathcal and mathscr use different
fonts (or styles of the same font). Also change some urls to use https.