Revert binary database block position encoding

This reverts commits a2003b0d553c7223a61c75e5dad79ea68e058ba2 and 54ffe2e5de9ce44129f84f4748743f893b75fda7.

These weren't correct.  Add a black magic warning instead.
Fix argument type of the RaiseException() function
Fix lost pause support in singleplayer
Revert "Add backtrace to error function"

This reverts commit 5b518ed2feff28c9bf21ad940c1b211b72d71bd1.

This caused duplicate tracebacks and tracebacks when unwanted.
It also ignored the level argument to error() and didn't pass the message (or level) to debug.traceback().
Use xpcall() or lua_pcall()'s errorhandler argument instead.
Update documentation on is_ground_content
Fix directional fog color in front view
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/database.h