Added itemstack handler

- Added itemstack handler (write,read,erase)
- Updated license
- Updated README.md with documentation

README.md

@@ -16,10 +16,50 @@ stratum.
 "metatools_stick.png" by Ataron (CC-BY-NC-SA)
 
 # Todo
- - Add a way to SET the metadatas (will be complicated)
- - Fix the LICENSE
+ - Add a check if set is done in Node/fields/
+ - Add a table handler for meta::set
 
 # Special thanks
  - mgl512 (Le_Docteur) for its locked itemframe which gave me the idea of a tool
 allowing to see/edit metadatas
  - Ataron who created the stick's texture
+
+# Command tutorial
+
+ - help										=> Get help
+ - open (x,y,z)								=> Open the node to manipulate at pos (x,y,z)
+ - show 									=> Show fields/path list at actual position
+ - enter <path>								=> Enter next stratum through <path>
+ - quit										=> Quit actual field and go back to previous stratum
+ - set <name> <value>						=> Set metadata <name> to <value> (create it if it doesn't exist)
+ - itemstack								=> Manipulate itemstacks in Node/inventory/*/
+	- read <name>							=> Read itemstack at field name (itemstring and count)
+	- erase <name>							=> Erase itemstack at field name
+	- write <name> <itemstring> [<count>]	=> Set itemstack in field <name> with item <itemstring> and count <count>. Default count is one, 0 not handled.
+ - close									=> Close node
+
+ Node metadatas look like this :
+
+ Stratum :	0		1		 2		...
+			Nodes/
+				|
+				+- fields
+				|	|
+				|	+-		foo
+				|	+-		bar
+				|	+-		...
+				+- inventory
+					|
+					+-		main
+					|		|
+					|		+-		1
+					|		+-		2
+					|		+-		3
+					|		+-		...
+					+-		craft
+					|		|
+					|		+-		1
+					|		+-		2
+					|		+-		3
+					|		+-		...
+					+-		...