Different ticket related method added

Hi!
I've added wrappers for some more methods in kayako.
Here's the list

* create/update/delete for Ticket
* create/update/delete for TicketAttachment	
* create/update/delete for TicketCustomField
* create/update/delete for TicketNote
* fetch for TicketPriority
* fetch for TicketStatus
* fetch for TicketType

For support of CRUD methods added httpclient dependency.

If you got any questions about code feel free to ask me