Fix #4 - Allow script to detect other keys types

Fix https://github.com/hashbang/hashbang.sh/issues/4
Fix incompatability with BusyBox Ash (and possibly other shells than bash).
Add configuration phase (usually unseen by the user, unless something goes
wrong).
Fix obsolete "local" variables (might be incompatible).
Fix checking for 'sed' (was actually using expr, not sed).
Fix issue with using until [[ -n $var ]]; which does not work with BusyBox Ash
($var is non-existant, yet this just skips the entire loop entirely).
Replace /bin/bash with /bin/sh and BASH with SH in sed templates.
Merge branch 'nonrsa-keys' of git://github.com/lollek/hashbang.sh into develop
Fix #1
Fix IdentityFile being full path, including ".pub".
Remove misplaced "exit" (what?).
Fix issue where dash, posh, bourne shell, yash, and possibly other Bourne-like
shells wouldn't work.
Fix broken support for Bourne-like shells.
Fix hashbang.sh using '==' instead of comparison operators -eq and -ne.
Fix comparing strings as integers.
Fix using string comparison for integers.
Use '=' instead of '==' for strings, for better POSIX compliance.
Fix using && instead of -a for AND comparison, to improve compatibility.
Update hashbang.sh script to follow new HTTPS and registration rules.
hashbang.sh: Now no longer uses keyType value.
Merge branch 'master' into develop
Ensure script exits with 0. No exit code specified does NOT mean "exit 0". Read
`man 1 exit`, section `EXIT STATUS`, for more information.
Merge pull request #7 from necrophcodr/develop

Fix #1, #4, and #6