Fix: key command and key emulation

[amadeo-alex]

This PR:

• replaces all usages of "keybd_event" as it has been superseded by "SendInput".
• fixes how the input emulation was handled - key was never officially "unpressed" - which caused issues with some of the applications (should remediate Bug: "Key" commands end up with key being "held down" HASS.Agent#323)
• made the "KeyCommand" modification UI display "keycode name" instead of "keycode number" (for example KEY_P)
• adds note to the "KeyCommand" modification UI about "TAB" key - LCTRL+TAB

I've tested both "KeyCommand" and MediaPlayer - both function as expected after the changes.

[amadeo-alex]

LAB02-Research/HASS.Agent#229 to be revised after this is merged

[kjack9]

I can confirm that #24 (specifically the changes in amadeo-alex/HASS.Agent.Staging/fix-key-command) fixes this issue entirely in Kodi. Previously I would skip between 2-8 lines when navigating up or down. Now everything works as expected. Thank you!

[kjack9]

LAB02-Research/HASS.Agent#276

This issue is also fixed by amadeo-alex/HASS.Agent.Staging/fix-key-command