Some security fixes

[valid22]

1. You must check for username if its alpha-numeric.
2. You must truncate blank or empty spaces on either end of username string
3. Bcypt password hashing has a limit for maximum no of characters in password, even tho tho it hashes md5 text am pretty sure client has some password limit
4. PDO Error mode is set true, you didn't catch any error. It's always good to try catch error at very basic step.
5. There are some columns in db, which are set to not null, so it throws an error while trying to insert a user.(This is a problem most user faces)

[Baysul]

I'll look into implementing your suggestions, but I have never experienced the last one. Could you please show me the error you're encountering?

[valid22]

@TunnelBlanket Basically I've not experienced that issue, but I've seen many people facing that issue and also reporting it. It mainly occurs on Igloo, Where during insert it throws a warning/error since it's set to NOT NULL