update cvar code from cvar_example project
just updating cmd code style to match cvar
Remove dynamic console command registration. Add struct ConsoleCommand to allow for static registration of console commands and remove cmd_s struct. Extract the command buffer code from cmd namespace and stick in a cmd_buffer namespace.
Wrap command arguments in a struct and remove global argument handling from cmd namespace. cmd::tokenise now takes an out CommandArgs parameter that it generates data for. Add tokenise tests to example application and patch up command functions to take CommandArgs parameter instead of global arguments query.