Adopt PSR-2 coding standard

- Now namespaced Resty/Resty
- protected methods calc_time_passed() and default_logger() are now 
calcTimePassed() and defaultLogger()
- Tabs -> 4 spaces
- VERSION = '0.6.0'
guard against empty $meta['wrapper_data']
use namespace path for \Exception
add Resty::jsonToArray($bool)

- default is false. if false, JSON is decoded to \stdClass object. If
true, decoded to array. `$r->jsonToArray(true)`
Update FUnit and clean-up/fix tests