Cannot use builtin (standard) libraries from gimp-gluas

[Marco Manfredini]

The standard, builtin lua libraries are not available in gimp-gluas. For example, using the math library (i.e. math.floor, math.random) yields the error message:

  attempt to index global 'math' (a nil value)

Eventually gluas example code which uses 'math' does not work anymore.

For unknown reasons, the initialization of all standard libraries in render.c was left commented out in gluas-0.1.20. The libraries base, io, str, math and tab were properly initialized before in gluas-0.1.19

Example patch initializes *all* standard libraries. This includes the os, debug and package library.