Port other major parts of PHP 4 COM extension into PHP 5 com_dotnet

Port other major parts of PHP 4 COM extension into PHP 5 com_dotnet
extension.
This enables:
- iteration of SafeArray types via foreach()
- proxying of multi-dimensional SafeArray types so that multi-dimension
  array accesses work (untested!)
- Fix COM exceptions, and expose them as their own class of exception
  "com_exception"
- auto typelib file import (com.typelib_file ini option)
- event sinking
- wrapper to map PHP objects to COM
- fix mapping of variant values to PHP values

# Could someone please add com_saproxy.c and com_wrapper.c to the .dsp
# file?