Add support for Alfred 4

Use latest version of AW

Update Alfred-Workflow

• Fix hanging background processes #4 (hopefully)
• Add new icons

Add fix #7

• Icons now reflect password security
• Alfred 3 only
• Option to turn off notifications #3
• Fix syntax error #5

This release will require updating any custom generators you've written.

Should prevent empty settings file issue.

Allow custom generators to be toggled on/off