Bug fix for case when no output function is provided

git-svn-id: https://svn.code.sf.net/p/vcftools/code@884 19d466ce-640d-45be-954f-fad4d9839663
Edited path to sourceforge repository on the website

git-svn-id: https://svn.code.sf.net/p/vcftools/code@885 19d466ce-640d-45be-954f-fad4d9839663
Added a man page for vcftools documentation

git-svn-id: https://svn.code.sf.net/p/vcftools/code@886 19d466ce-640d-45be-954f-fad4d9839663
Bug fix for a few output functions that break when sites do not pass filtering

git-svn-id: https://svn.code.sf.net/p/vcftools/code@887 19d466ce-640d-45be-954f-fad4d9839663
Merge remote-tracking branch 'upstream'