added desc to rake file

Added add’l description to the rake file tasks (run rake -T)
Make it clearer that config arg is required for most commands

Add note about config path
Merge pull request #100 from i-like-robots/master

Make it clearer that config arg is required for most commands
fixed explicit paths in config
rm gemfile.lock
minor gallery change
Merge branch 'master' into fix_explicit_paths
Merge pull request #102 from BBC-News/fix_explicit_paths

fixed explicit paths in config
Merge pull request #92 from sbelyea/master

added desc to rake file
Merge branch 'master' of https://github.com/BBC-News/wraith