Don't leak memory when failing to load CRN or KTX cubemaps.
Make the TTY console the default

* +nocurses is replaced by +curses to ask for a curses console
* remove USE_CURSES from the cmake options
* actually use curses only on Linux (other platforms are broken/not supported)
Use curses on windows TTY client and server
Remove cl_logs.cpp a similar functionality is provided with logs.logFile
Also remove the prototypes for cl_logs.cpp
cl_irc.cpp: use unordered_map for the command htables
Remove qcommon/htable as it is no longer used
Enable the curses console for the Windows tty client and server
cm_load.cpp: remove the unused checksum argument from CM_Load
Remove qcommon/md4 because it isn't used anymore
Add back +nocurses
Remove the client debug graph and associated cvars
Remove the compile time option USE_MUMBLE as there are no drawbacks to always having it true
Revert "Add the S_{Begin/End}Registration syscalls and use them in cgame"

This reverts commit 888c89a24186627485458b25036f99ae4fd3d9be.
Merge remote-tracking branch 'origin/master' into gameplay/testing