Update requirements.txt
Update example.toml to use 'sellable' + 'buyable'
Merge pull request #160 from sbwdlihao/localization-support

Localization support
Now automatically try to guess best language from those available.
Adds a language selector + session vars to track the selected language
Missed a bit
Merge pull request #7 from simplecrypto/master

merge from simplecrypto