Fix incorrect usage of NewWithFilename
Merge pull request #4 from bcwaldon/patch-1

Fix incorrect usage of NewWithFilename
Correctly identify when user is not detected
Merge pull request #5 from bcwaldon/patch-1

Correctly identify when user is not detected
Add NewWithOptions constructor

The NewWithoutOptions function can be given an explicit set of
options, allowing a user to create a GlobalConf object with
no associated file on disk.
s/ConfigFile/ConfigFilename
Update README with latest changes
Use ptr to Options in NewWithOptions
s/ConfigFilename/Filename/g