CCBC-565: make cbc prompt for password if pass is '-'
CCBC-565: make cbc prompt for password if pass is '-'

This allows a user to securely enter their password on the terminal,
without having to specify it on argv; as argv parameters can be obtained
via `ps`

On POSIX systems password input is masked via the POSIX termios
functionality.

Change-Id: I8bf4823a4eb0a1969658f994f8da4d084adc6b11
Reviewed-on: http://review.couchbase.org/45153
Tested-by: Mark Nunberg <e7d42768707bf23038325b0b68d4b577e5f6064a@haskalah.org>
Reviewed-by: Sergey Avseyev <87f6d5e4fd3644c3c20800cde7fd3ad1569370b3@gmail.com>

avsej/libcouchbase,signmotion/libcouchbase,PureSwift/libcouchbase,senthilkumaranb/libcouchbase,PureSwift/libcouchbase,signmotion/libcouchbase,signmotion/libcouchbase,couchbase/libcouchbase,avsej/libcouchbase,kojiromike/libcouchbase,kojiromike/libcouchbase,kojiromike/libcouchbase,mody/libcouchbase,mody/libcouchbase,couchbase/libcouchbase,senthilkumaranb/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase,mody/libcouchbase,couchbase/libcouchbase,maxim-ky/libcouchbase,avsej/libcouchbase,maxim-ky/libcouchbase,senthilkumaranb/libcouchbase,signmotion/libcouchbase,maxim-ky/libcouchbase,mody/libcouchbase,avsej/libcouchbase,PureSwift/libcouchbase,PureSwift/libcouchbase,avsej/libcouchbase,avsej/libcouchbase,senthilkumaranb/libcouchbase,kojiromike/libcouchbase,avsej/libcouchbase,maxim-ky/libcouchbase,couchbase/libcouchbase,couchbase/libcouchbase