unpack error

[Nolan James Dyck]

Lines 168, 170, 174 raise errors when run with Lua 5.2:

lua: .\slaxml.lua:168: attempt to call global 'unpack' (a nil value)

unpack has been moved into the table table in Lua 5.2.

Inserting the following line at line 38 solved the issue, and should make the file compatible with both Lua 5.1 and 5.2:
local unpack = unpack or table.unpack

[Gavin Kistner]

Fixed in release 0.5.2, by commit 2a9bfbc