Box Backup

Disable HTTP keepalive for now because we don't support it properly

Increase S3Simulator HTTP timeout to aid debugging

Improve exception messages when reading an HTTPResponse

Fix check for existing BackupStoreInfo? file on S3 stores

Whitespace, import order and comment fixes

Allow verifying a BackupStoreFile? without closing underlying stream

Make wrong return type an error, not a warning. We should never fail to return something from a non-void function.

Add missing header include. Fixes compilation on Windows.

Don't overwrite OpenSSH Makefile during extraction. Hopefully should allow previous compilation results to be cached, when combined with not running ./Configure if the Makefile already exists.

Add script to compile Box Backup and dependencies on Windows (Cygwin). Automates the instructions found in docs/api-notes/win32_build_on_cygwin_using_mingw.txt.