NSURLSession based network layer WIP
Tests for URL encoding and query parameters
Minor renaming
Support download tasks
Multipart upload support
Removed use of AFTHTTPRqestionOperation
Removed all references to AFNetworking
Escape all form encoded values
Better handling of server side errors
Removed mimeType from PKTFile methods
Return task handle for network operations
Do not return task handle for -[PKTClient performBlock:]
Added time component support to PKTDateRange
Merge pull request #5 from podio/new-network

NSURLSession-based network layer replacing AFNetworking