xdebug-not-done -> xdebug

Summary: This changes the `XDEBUG_NAME` macro from `xdebug-not-done` to `xdebug` and also xdebug ini settings from `hhvm.xdebug-not-done.*` to  `xdebug.*`, matching php5 xdebug. This just involved a find and replace and updating `xdebug.enable` to use ini instead of hdf.

Closes a TODO in #3704.
Closes https://github.com/facebook/hhvm/pull/3779

Reviewed By: @ptarjan

Differential Revision: D1563675

Pulled By: @paulbiss
Fix annoying typechecker tests that have to be updated with every single change

Summary: I didn't know that hh_show works that way when I wrote them. I switch them to instead pass the value to functions and use the lack of error message as a verifier. It's not checking it as strictly as comparing hh_show, but the current approach is not acceptable.

Reviewed By: @jwatzman

Differential Revision: D1606478
Implement readline_info()

Summary: Used php-src for this.
readline is now at 100% good zend tests
Closes https://github.com/facebook/hhvm/pull/3799

Reviewed By: @JoelMarcey

Differential Revision: D1568453
Unbound fixes #2

Summary: Me again, sorry! So after the last issue discussion, here I am adding hhi unbounds manually when I encounter them.

- Added constants to file, json, mb, and a few string modules
- Added finfo module
- Added lots of reflection stuff
Closes https://github.com/facebook/hhvm/pull/3726

Reviewed By: @jwatzman

Differential Revision: D1550354
remove FOLLY_OVERRIDE usage in hphp

Summary: we currently have a mix of using 'override' and FOLLY_OVERRIDE so the macros do not help anything.

matches the removal of FOLLY_FINAL from hphp.

Reviewed By: @jdelong

Differential Revision: D1607671