RExecServer object vending

The RExecServer started getting basic object vending today. To test it out I implemented some simple object copying using Distributed Objects. This is checked into the public git repository, but will require R-devel to run because of changes to function export under R-devel. Behold!

First we start ourselves a couple of copies of R. Then,

> x = 1:100
> .Call("RES_CopyObject","x","R Execution Server 2")
NULL
> .Call("RES_ServerName")
[1] "R Execution Server 1"
> 

Afterwards, we can take a look at the other execution server:

> ls()
[1] "x"
> .Call("RES_ServerName")
[1] "R Execution Server 2"
> x
  [1]   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18
 [19]  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36
 [37]  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54
 [55]  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72
 [73]  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90
 [91]  91  92  93  94  95  96  97  98  99 100
> 

Ta Da! There's no big trick to it--we're just using the standard serialization routines to read and write NSData objects on the Cocoa side and then using the usual NSDistantObject routines to actually transmit the data. There's no real error checking at the moment, but that will come.

Also, with the help of some scripts from Rob Goedman I think I've tracked down the last of the clipping and state stacking errors in this latest checkin.