Reading #!r6rs from string affects writer's behaviour

[Takashi Kato]

Following code;

(read (open-string-input-port "#!r6rs"))

changes writer's behaviour to R6RS mode.

[Takashi Kato]

Modified load to pass read context to read a datum so that it can detect #! (Fixes #20)

→ <<cset 267bca1ac86e>>