Compat support upto API Level-5 Eclair.

Hi Steven,

I have made  AccountSuggestTextView support upto API: 5, I have picked Email-Pattern from latest android-L sources , Please check below link for quick reference.
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/5.L_preview/android/util/Patterns.java
Also I modified AndroidManifest & README to reflect new changes. 

Please check my Diff & Accept Pull request quickly.

Thanks
Biraj Patel