Cmd: Rename a bunch of functions
Cmd: Remove Cmd::Args::Iterator

It seems that it will have almost no use (which command
iterates over all its arguments starting from 1? /buy /sell and that's
all).
Cmd: Change the way static commands are handled
Cmd: implement /list<Subsystem>Cmds
Merge branch 'gameplay/viech' into bots+viech
Implement Args::GetArgs.
Mark Args::GetArgs() as inline. (Fixes build error.)
Args::operator[] for access as if array. (Uses Argv(int).)
Fix an off-by-one if the command string being split does not have trailing white space or ';'.
Drop empty commands at the earliest opportunity.
Cmd: rewrite vstr and exec
Cmd: enum cmdFlags_t -> int for flags
Replace most of the references to Cbuf_*
Cmd: port /delay and related commands to C++
Cmd: /delays are user input
Cmd: remove more C code
Cmd: port echo,concat,random and remove /wait /calc
Cmd: Use a vector instead of a list for the command buffer
Cmd: Added Args constructor from vector
Cmd: Fixed RawArgsFrom