Modules manager

Description

modules manager functions

addgateway - Adds dynamically builtin at runtime.
addmodule - Add module to Nelson.
gatewayinfo - Returns information about an gateway.
getmodules - Returns list of modules loaded in Nelson.
ismodule - Checks if a module is loaded.
module.json - module.json description
modulepath - Returns path of a module.
nmm - Nelson Modules Manager.
nmm_build_help - helper's function to build help of an external module
nmm_build_loader - helper's function to build main loader.m of an external module
removegateway - Removes dynamically builtin at runtime.
removemodule - remove a module from Nelson.
requiremodule - Returns an error if module is not loaded in Nelson.
semver - semantic versioner.
toolboxdir - Returns path of a module.
usermodulesdir - Returns path where external modules are saved.