Most changes are variable renamings because elm does not allow masking
a visible name anymore.

Deal with changes in the standard library, especially in the Parser
interface.

Source files must now start with a capital letter.

Dockerfile: remove unneeded dependencies, install nodejs from debs.

Remove the redundant Maybe from the return value of readstring.

Stop embedding the colon in keyword represenation.

Remove obsolete comment.

Fix a typo and avoid an unneeded function mapping.

It was necessary to rename some ambiguous variables. Some more names
could probably be changed in order to reduce the diff with kanaka#450 (my
names were choosen in order to reduce the diff with master...)

Peek ideas from kanaka#450:
- sort imports
- skip a line between '->' or before 'else'
- no indentation after 'in'
- fix indentation when it was only intended to reduce diff
- remove some unneeded parenthesis
and
- if .. return True else False -> ...

Various trivial changes reducing the diff to kanaka#450.

Dockerfile: npm already depends on nodejs

Core.elm: change profile of deepEquals instead of uncurrying before
each call.