sag -g filename support

[premek]

It would be nice to support this scenario. Expected: to open a given file with F Actual:

$ sag -g filename
sack__option is: -ag

============> running ag! <============

===> Current Profile: no_profile
===> Using flags: 
===> Searching under: /home/etc/etc
===> Searching parameters: -g filename


/home/etc/etc/filename
[1] 

$ F 1
sed: -e expression #1, char 10: unknown option to `s'

And it opens the editor in working directory

[SnoringFrog]

I realize this is quite an old issue by now, but my recent fork fixes this https://github.com/SnoringFrog/sack