Version a0.8.20 is out

Version a0.8.20 - Release notes:

Features:

1. In the main HUD you can now see the current sector coordinates and threat level.

Modding:

1. Weapons can now add or remove O2 from the impact cells.  Example: In the weapon model set the parameter OXYGEN=100 or -100 (it's in % of the max O2 in a cell) 
2. Weapons can now be non hostile.  Example: In the weapon model set the parameter HOSTILE=0 
3. Unrecognized event, dialogue and model parameters are now shown in logs.

Bug fixes:

1. SERVER_VARIABLE_PRESENT/ABSENT conditions - fixed any_value parameter
2. Ship AI ai_id - fixed saving set ID
3. When Teleporting multiple mobs/players they no longer get melded like in the old movie The Fly