Its output will rise when (positive > negative + window/2) and fall when
(positive < negative - window/2).

	new file:   block/block_schmitt_trigger.c
	modified:   block/build.mk

The block will output 'true' when input positive >= input negative.

	new file:   block/block_comparator.c
	modified:   block/build.mk

Add realloc function to controller_mem
Move reallocs in blocks to new controller_mem functions
Add test case for block_state_machine.

Move some more time related stuff to controller_time
Add code to handle skipped samples.

	modified:   controller/block/build.mk

Add the 'pand' block.

	modified:   controller/block/build.mk

Don't try to link against 'libdl' on FreeBSD. dlopen() and friends are in libc
there.

Cleanup libs
Add lib dependancies for console_httpd.
Add inf as double constant.

Lots of test updates

Fix some setpoint generator quirks

New 1d setpoint generator for simple control
Added test blocks
Added tests for some blocks
Removed broken iir_test

Fix block dependencies

Added integer variables (nice for defining named states in the state machine)
Various improvements to a few blocks
	joystick uses controller bus
	multiplexer and trajectplayer can handle non existing selects
(cherry picked from commit 82abe0ef)