avcodec: align dimensions only for software decoding

There is no use to CPU memory edges when decoding in hardware (arguably
libavcodec should be "enhanced" to not add them in that case).
This unbreaks VDPAU.
Add subdir-objects automake option where appropriate

Makes version 1.14 happy.
Update to gettext 0.18.3.1, fix AC_CHECK_DECLS usage
omxil: vout: Handle dynamic aspect changes.

Handle changes of aspect ratio through the Control handler.

Signed-off-by: Julian Scheel <julian@jusst.de>
Signed-off-by: Martin Storsjö <martin@martin.st>