`exec` like command for other murex processes

[lmorg]

Currently there is an exec command for forking external processes. There should be one for other murex processes so commands can be specified where namespaces clash.

Proposed builtin: fexec (function execute)

• --function
• --private
• ~--alias~
• ~--autocomplete~
• ~--event~
• ~--open~
• --builtin

[lmorg]

alias and autocomplete would require too much work to complete:

• alias is a problem because of the way aliases are processed in murex:

  executeProcess:
  witch {
  ase GlobalAliases.Exists(p.Name) && p.Parent.Name != "alias" && !parsedAlias:
  // murex aliases
  alias := GlobalAliases.Get(p.Name)
  p.Name = alias[0]
  p.Parameters.Params = append(alias[1:], p.Parameters.Params...)
  parsedAlias = true
  goto executeProcess
  
      case MxFunctions.Exists(p.Name):
      // ....
  

  ie we don't know what an alias points to before running the alias
• autocomplete because dynamic blocks can be deeply nested inside the autocomplete config.

[lmorg]

event and open require parameters passed to them. So might need some careful thinking before implementing