New Features: Defect Introduced Date and Author with delimited email

This adds two prefs that my company is going to be using. 

Defect Introduced Date: This lets the user set a defect introduced date and when sonar runs it will automatically assign defects when they were created after the date set in the pref. This is useful to us because we have a large existing code base and would like to get all the old defects assigned out. 

Author with Delimited email: This is useful for us because our git Authors have the form: First Last <email@email.com> because it's not a username or email address your plugin wasn't working for us, I added the pref so we could set the start and end characters for the email address in the author name.

I think these could be useful to others which is why I'm sending them back to you. Please let me know if you have any questions or if there is anything I should do before you can accept this. I'm not familiar with maven or mockito tests but I tried to do my best to keep everything working.

Hardy