adding license.txt and removing it from the header.

fixes #42
adding one space to comply with coding conventions
Adding a security check to prevent files from accessing the boilerplate directly

Fixes #43
Removing tabs and spaces on empty lines

Related #44
replacing all midline tabs and replacing the with spaces to comply with the coding standards

fixes #44
adding get text and plural forms to the .pot file

related #40
adding a text domain to the plugin header

fixes #40