Using tabs consistently

[jman]

Hello everyone,

the file ./src/passwordstore.sh uses tabs instead of spaces but not consistently. The last HEREDOC 
in function `cmd_usage()` mixes tabs and spaces for formatting reasons. This mix makes complicated 
for me formatting patches, I have to manually discard hunks before submitting the patch.

What's your workflow to avoid this manual mangling when submitting patches here?

Thanks!

Regards,