Fixed a bug that prevented player heads placed on walls from being saved correctly.

Added function SkNBTAllPlacedBlocks(string) to return all placed blocks by name

Now blocks that are registered by SkNBTPreserver will be immune to pistons and physics. This was added to avoid issues.

Maybe I will add a way to track an nbt when a block is moved/changed.

Changes:
* From now SkNBTPreserver will save your block only if it has a custom name. The reason is to avoid registering useless things.

Fix:
* Fixed a bug when breaking registered blocks dropped their loot in creative.

* Fixed an issue when placing a block would not register it if it was the last in your inventory

Major improvements!

* Fixed a lot of bugs
* Added /sknbtpreventer command (alias: /sknbtp, /sknbt)
* Added /sknbtpreventer check to check all registered blocks
* Added /sknbtpreventer purge to check the database for removing useless data
* Added /sknbtpreventer search to show all blocks in the server. You can search by name (n:<name of block) or by player (p:<player>)
* Added /sknbtpreventer removeall <name> to remove all blocks by name
* Added some functions:
- SkNBTRemoveAllBlocksByName(string)
- SkNBTRegisterMoreData(block, data, value)
- SkNBTPreserverRemoveBlockNaturally(block)
- SkNBTPreserverRemoveBlock(block)

Enjoy !

* The frequency of block checks is now set to one minute. You can change this if you want.
* Added a condition to check that the broken block is of the same type as the saved NBT. (Helps prevent duplication bugs or others)