Fixed broken carpet handler [SEE DESC]

Made BlockHandler pass on control to carpet handler
Declared thinggummies in carpet handler
Fixed carpet block pushback using incorrect format
Fixed longstanding issue with slabs

Fixes FS#298
Changed comments to be more accurate
Removed unwanted VirtualHooks remnants.

cEntity no longer needs its SpawnOn() default-implemented, it can now be a true pure virtual function.
Fixed AddHook() wanting old-style function names.

Error reported by STR_Warrior in the forum http://forum.mc-server.org/showthread.php?tid=1227&pid=9620#pid9620
Fixed lighters replacing blocks
Double slabs work *choke choke*
Fix VSProject path issue
Fixed incorrect double slab drops
Change the gitignore, fix #122
Fixed final slab bug

This bug allowed a double slab to be made below by placing a compatible
slab on a "top" slab. The coordinates are always one lower, so now it
checks to see if the slab orientation can be made into a double.
Added Unicode, Inc.'s notice.

Fixes #123.
Added comments and fixed a bug

Bug was placing slabs between slabs not making a double slab.
Fixed inconsistent metas and added snow metas
Client can no longer place blocks outside the Y range of the world.

Fixes #128.
Fixed pickup behavior outside the world.

One part of #131.
cTracer doesn't attempt a trace above the world.

This fixes some crashes with out-of-world entities.
Slight performance improvement in cWorld::FindClosestPlayer()
Lifted the debugging 1 GiB RAM limit in LeakFinder to 1.5 GiB
Fixed logging in cTracer.