Add feature: XSECURELOCK_WANT_FIRST_KEYPRESS=1 xsecurelock.
Add feature: XSECURELOCK_WANT_FIRST_KEYPRESS=1 xsecurelock.

Many other screen savers send the wake-up keypress to the auth dialog,
so let's offer this feature to. Do read the security notes about this in
the source, though.

Fixes #14.

google/xsecurelock,google/xsecurelock