Add functionnalities to proost (toplevel)

Add syntax coloring, hinting, multiline editing, parenthesis checking and highlighting.

assigned to @aalbert

created branch 39-add-functionnalities-to-proost-toplevel to address this issue

mentioned in merge request !37 (merged)

added To review label

closed with merge request !37 (merged)

mentioned in commit 93bdf20f

mentioned in commit a963b0d7

mentioned in commit 9b2abf15

mentioned in commit a7bf0044

mentioned in commit c9508250

mentioned in commit b33886cb

mentioned in commit 1f0aa51e

mentioned in commit 48c1becd

mentioned in commit bcbd4faf

removed To review label