Use released fog 0.15.0.
Use mutli_json gem instead of json.
Allow use of fog's credentials file.
Merge pull request #13 from nosborn/fog_0_15

Use released fog 0.15.0.
Release version 0.2.4
Merge pull request #14 from nosborn/multi_json

Use mutli_json gem instead of json.

Merged after discussion with @danielabel
Merge pull request #15 from nosborn/credentials

Allow use of fog's credentials file.

merging after discussion with @danielabel and @dancarley