Added a voice announcement system for the AI.
Voices are based on /vg/'s female voice and are copyright free.
There is a 60 second cooldown for each announcement.
Added a compile option for AI voices. Undefining AI_VOX will not compile the resources, meaning players won't have to download them.
The AI's vocal announcement will also make a Request Console style announcement with the text of the message.
 * Removed the text announcement. It wouldn't work if the AI used the sound effects.
Adds missing "wood.ogg"
Merge pull request #1 from JJRcop/wood-ogg

Adds missing "wood.ogg"
Removed follwing silence from sound samples

I KILL YOU, SILENCE
Merge pull request #2 from JJRcop/silence-i-kill-you

THIS IS THE DAY SILENCE DIES
* Added a changelog entry for it.
Merge branch 'master' of https://github.com/tgstation/-tg-station into ai_vox_boogaloo
Removed the HL sound effects.
Made period and comma sounds completely silent, and turned them Vorbis
Merge pull request #3 from JJRcop/comma-period-silence

Background sound removed from period and comma sounds, also they are now Vorbis
 * Removed the deleted files from vox_sounds.dm
Merge pull request #1658 from Giacom/ai_vox_boogaloo

Added a voice announcement system for the AI. [CHANGELOG]