Small tweak to idle_loop()

In case of a succesful late join we set again
'searching' flag, so we can restart search
immediately without an useless lock/unlock
cycle.

No functional change.
Simplify Time Management UCI options

No functional change
Retire struct Log

No more used now that we have removed
"Write Search Log" UCI option.

No functional change.
Rename "Contempt Factor" to "Contempt"

Suggested by Ronald and Lucas on talkchess.

No functional change.

Conflicts:
	src/ucioption.cpp
Merge branch 'master' of https://github.com/official-stockfish/Stockfish