Updated testing version 0.51

Updated test version for Custom items
added preliminar support to custom hints.
Updated Custom item sell.

Now you can add descriptions to your items with the command /rssetprices add ID:[DATA]:COST:[MIN]:[MAX] description. All arguments after the price/ID one are considered description for that item.
Updated Custom item sell #2

[FEATURE] Now custom items can be shipped.
[FEATURE] You can sell custom items with durability and they will be treated as different if used. This will avoid an user buying an item, using it then sell it back to store.

[BUGFIX] Shipping items will not remove them from the shopping cart, duplicating it.
[BUGFIX] Shipped tools will have their durability set to 0.
[BUGFIX] Spaces in description when adding prices are not considered.
[BUGFIX] ID saved in prices.xml has too much information.

-- Code related changes
[UPDATE] Long if-else chains whit strings were replaced with Switch(String) where possible.
[UPDATE] When adding a price for tools their durability will be considered as a difference factor. Hash for meta is calculated with this formula: (metahash + (durability * price))*price 


[DOCUMENTATION] Added lines of documentation for some methods. This is a preliminar add, the next ones will be added in future commits.
Updated Custom item sell #3

[BUGFIX] Commands are case sensitive.
Updated Custom item sell #4

[FEATURE] Custom items can be shipped and retrieved. (needs testing). You can only ship items you already bought from the store.
[FEATURE] Added preliminar support to itemstack serialization for temporary shipment package saving.

[BUG] Distance fee is not applied to shipped packages.

-- Code related changes
[FEATURE] RSInventory now stores all bought items for every store session. Now we can get track on every bought item until the player leaves the store. This feature was added for item shipment.
[CLASS] Added ShippedSerialization class for easy serialization to YAML of ShippedPackages object. This class helps with loading and saving yaml of ShippedPackages.
Merge conflicts resolved.

Now ready for full merge with Kuben's repo.
Updated /rsprices on ItemFrame.

[FEATURE] If you right click on an itemframe within 3 seconds since the first click, the frame will display the next page.
[BUG??] right click within the time limit will increase the page even if there are not so many pages. (it could be annoying but I think not, because passed the limit the pages are setted to 1 again)
Updated /rsprices on ItemFrame #2.

Fixed code to avoid hangs and null pointer exceptions.
Updated /rsprices on ItemFrame #3.

Fixed possibile Array out of bound Exception
Merge pull request #5 from stengun/customitems

Customitems