Update 37coins_en.properties

Doing it directly in github now. Made some grammar changes. Made some things consistent, such as PIN. Rewrote some other items as well.
Grammar and consistency changes.

Trying on github directly now. Made some grammar changes and updates to the writing.
Update grammar and consistency 

tried doing it directly here on github. Lets see.
Merge pull request #24 from gianni-dalerta/master

English revisions, thx to gianni