Merge pull request #10 from afalkear/master

Added trimming option before validation
version 0.0.15
gemfile.lock
[#53918021] avoid exception when contact_attributes is not available
version 0.0.16
[#53918021] BelongsToContact gets all attributes from api
version 0.0.17
add ContactAttribute.custom_keys
[#54211426] added find_by_kshema_id method to contacts client
[#54211426] uses ActiveSupport::Json.decode