Merge branch 'release/0.1.1' into develop
Avoid extra whitespace on output.

Suppress extraneous newlines when code output already ends in a newline. Write a return character to indicate when we automatically insert newlines to make things pretty :)
Add “used” variables to the Closure presenter.
Keep the input buffer open if a line ends with “\”

e.g.

>>> 1 \
... + 1 \
... + 1
Don’t run the shell automatically when the psysh bin is included.

Fixes #48
Fix STDERR and STDIN while running as the CLI SAPI.

For some reason, the CLI SAPI doesn't define STDERR and STDIN constants, even though 'php://stderr' and 'php://stdin' still work like you'd expect.

This only affected people without Readline or Libedit. Seriously, folks, install PHP with some sort of Readline support. It is so. much. better.

Fixes #54
Work around complaints when initializing shell from CLI SAPI.
Version bump v0.1.2
Merge branch 'release/0.1.2'