Switch back to C99 and add some LTO fixes.

This switches the project back to C99 by default, since we no longer use C11 anywhere. If C11 is used, we can just enable it easily enough. This also adds some fixes
for compiling with LTO enabled.
Implement basic set of HAR specific palette tricks (#204).

This implements a basic set of the HAR specific palette tricks, such as pyros torch heat effects. Note: Some of the p<x> tags are still unknown, so this is
likely not the full implementation.