README Usage (command line tool) correction

[smartexpert]

In the Usage (command line tool) section, after the text "To add a new annotation, you usually test the selection criteria first:"

The command says:

scrapely> a 0 w3lib 1.1

which should be corrected to:

scrapely> t 0 w3lib 1.1

Also in scrapy command line:

help t 

prints

ts <template> <text> - test selection text

when it should print:

t <template> <text> - test selection text

Just adding these for the benefit of other who got confused like I did.