Swift package manager support added
errorTextLable property added to change text color of error label

Swift 4.0 support added.
RTL support added.
some bug fixes

iOS Bug Fixing

Resolved crash of iOS 11.

• some bug fixed

• dtLayer animation issue resolved
• some other bug fixing

• Left view, right view and clear button frame issue resolved.
• showError and hideError methods added to toggle error label.
• floatingDisplayStatus variable added to maintain floating label (always, never, defaults).
• textPlaceholderRect and textEditingRect frame code updated.

DTTextField code optimised.