Cache DateTimeFormatters

DateTimeFormat.forPattern() caches the DateTimeFormatters, but it must
synchronize on a HashMap to do it.
Create GenabilityClient

Acts as a factory for service classes. Populates created service
instances with appId, appKey, restApiEndpoint, etc.
Upgrade dependencies
Create a client class, which acts as a factory for services
Add GetLseRequest and GetLsesRequest
Get rid of the trailing _ in field names for consistency.
Clear eclipse warnings
Use generics to eliminate unchecked casts
Update getTariffs request
Update Price, PriceChange and PriceService
Add JUnit test suite
Moves tests out of 'test' package.
New tariff models
Ability to set min/default/ext fields in request
More model classes and fields
Add isActive and hasTimeOfUseRates
Use enums whereever possible
Season and SeasonGroup
Fixes
New enum values