Allows short form with number of arguments and long flexible form with table:
```lua
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler', { '$argument.0=' })
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler', { 0 })
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler', { [1] = 0 })
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler', 1)
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler', 0)
```
Also, there are way to pass no arguments at all:
```lua
rtorrent.insert_lua_method('d.watch_handler', 'watch_handler')
```
Type checking added.
Deep-copy `__namestack` decouples all instances of Autocall, previously it
worked as singleton. This allows to store call-chains as variables, aliases.
Target-object allows to avoid duplication of the target-parameter as required
with Autocall by storing them as variables.
Autocall_config renamed to Autocall for brevity.
Trying `rc.print()` causes redirection to native global Lua `print()`, which
prints to stdout. I don't see any proc of shor-circuiting `autocall_config`
with global environment `_G`.
PRESFIL