linuxcncrsh: use the non-deprecated way to specify signal handlers
linuxcncrsh: ignore SIGPIPE at startup, not after thread creation

Signal disposition is a process-wide setting, not a thread-specific
setting.  So set the disposition of SIGPIPE once and for all at program
startup, instead of each time a client connects.
un-race-ify the linuxcncrsh client connection logic
now that connecting to linuxcncrsh is not racy, we dont need sleep

Sleep always seems like a quick and convenient way to fix your problems
at the time. But it's not!  Never sleep!
linuxcncrsh: dont bail on errors from parseCommand

The return value from parseCommand() is ambiguous and useless, so
ignore it.
Docs: Fix a typo left over from rebranding

Change LinuxCNC2 to LinuxCNC, in four languages.
Not five languages because French was already done,
thanks, Francis!

Signed-off-by: Kim Kirwan <Kim@KimKirwan.com>
Docs: Fix typo left over from rebranding

Found another one.
Changed LinuxCNC2 to LinuxCNC in one file.
I think that's all of this kind.

Signed-off-by: Kim Kirwan <Kim@KimKirwan.com>
keep 2.5 in synch with master docs