Many of the gears treat non-0 timer as overridden. Added that check in more places so that lua could use this a tiny bit more consistently. Also preserve state for jetpack.
use BUILD_SHARED_LIBS to control whether a library is shared or static, make our bundled physfs library check for this configuration
added images and corrected bug that didn't show correct description at some occasions
issue #562, image and description for the campaign page