rawls the web for email addresses. The program will start on a given web page, scan the (text) page for email addresses, and then follow the links on the page to look for more email addresses.
Input:
url - initial URL for the crawl (depth 0)
max_depth - maximum depth of the crawl
max_pages - maximum web pages crawled
Output:
all email address found on all crawled pages and the url it was found on.