Indented multiline literals

The E parser and printer fail to be consistent when given a string literal containing a line break. It would also be useful to have syntax for multi-line string and quasi-literals which is indifferent to the level of indentation in human-written programs.

Proposals
Several made in. [If opinions are expressed, expand this section to mention them specifically.]

Discussion

 * Initial report by User:Kevin Reid.
 * Second report by Kevin Reid (who forgot he had written the first)