Updated max lenght of username field in password-reset form

As the password reset form can also accept emails, increased the max-length size to 50 - so that we can accept long emails too.
Increased password-reset form username size to 100

Increased the accepted max-length to 100 as requested:  https://github.com/TheSerapher/php-mpos/pull/1279#issuecomment-31732351
Merge pull request #1279 from raistlinthewiz/next

Updated max lenght of username field in password-reset form