only make rmspell and mkdirspell show up after talking to the vendor

[mprat]

[luffah]

hello, in my fork, the spells appear but you shall buy it to the vendor with the money you found in his bag:

• 'ls' show 'backpack', 'rm', 'mkdir' and 'vendor'
• 'less vendor' tell you choices to buy either rm or mkdir. If you validate, he says you don't have the money
• 'less backpack', say you it is zipped. 'backpack' become 'backpack.zip' and you're allowed to use 'unzip'
• 'unzip backpack.zip' add 2 items corresponding to the costs of the 'rm' and 'mkdir' spells
• 'less vendor' ....