New Features

• Add send types AnyDriver, DD and SendInput (DD: @dbgba)
• New API: IbAhkSendSyncKeyStates (IbSyncKeyStates)

Enhancement

• Thread-safe (@任性)

Changes

• API change: IbAhkSendInit
• API change: replace IbAhkSendInputHookBegin and IbAhkSendInputHookEnd with IbAhkSendInputHook
• Replace the unit test framework with Boost.Test
• Add MIT license

Fix

• Fix error messages (@任性)