Headless gecko browser attempt 3

I reported my trouble in the comments of the bug which first proposed a new headless renderer. I got helpful comments from both Chris Lord and Sylvain Pausch, basically if your embedded application segfaults like this:

WARNING: NS_ENSURE_TRUE(compMgr) failed: file nsComponentManagerUtils.cpp, line 165
###!!! ASSERTION: You can't dereference a NULL nsCOMPtr with operator->().: 'mRawPtr != 0', file ../../../../dist/include/xpcom/nsCOMPtr.h, line 796
Segmentation fault

Make sure you have MOZILLA_FIVE_HOME environment variable pointing to the directory containing libxul.so ($prefix/lib/xulrunner-1.9.2a1pre/) when running the sample.