Persist newlines across server

[danielbinder]

Newlines are usually filtered out as soon as they reach the server, but we may want to persist them as much as possible, since e.g. error messages are shown in the actual line they occur instead of always showing line 1.

Tasks:

• Go through the 'I want to make a change' checklist
• Find and change this at places where it where it is possible to preserve newlines e.g. the parenthesiser.
• It does not make as much sense when something is transformed e.g. with simplify, but it would still be nice, if possible!
• Don't forget to add tests for this wherever you add it - newlines are often very tricky and can lead to some unexpected errors!

[danielbinder]

This is unfeasable effort for no real gain