This is a fix for Issue #55. Changes made:
* Server ignores intangible entities when determining if a building placement is valid (fixes func_breakable issue)
* If a func_weldable has the "welds open" spawnflag set, then upon completing the weld when it plays the break effect, it will become fully intangible. It will reset upon round restart.
Fix by @RGreenlees
Fix for issue #94.
Gorge web strands now have hit detection which matches their visible component. This is for both ensnaring marines, and for cutting them with a welder.
This has the following impacts:
* Webs are easier for marines to avoid since they can safely jump or duck under angled strands, however...
* Webs are harder for marines to cut as they can no longer clear a while corridor with a single click but have to actually aim at each strand
