Extends support for add-ons and add Freemius

Commit log

b96dc9b Updates the changelog
15fce8e Hides the freemius secure warning
a44d182 Fixes row width
44e1973 Add freemius sdk
7f656c2 Merge branch 'development' of https://github.com/OSTraining/EmbedPress into development
4300234 Change preview to support additional urls coming from add-ons
7175554 Change preview to support additional urls coming from plugins
da2c815 Removes executable permission
7138621 Fixes the size of fields in the modal window
9a09658 Merge branch 'development' of https://github.com/OSTraining/EmbedPress into development
c9c381c Removes block for when a embedpress is not active
c995def Minor fix for tabs
2531e8d Optimize logo in settings page
2c8384e Prepares for release
e804614 Add version to the settings asset
781796a Adds support for color picker settings field in add-ons
7a53b54 Prepares to release
d8f9f4b EPRESS-103 Fixes PHP warning for Gists
5b4dfa8 Fixes file permissions
71b4eed Fixes file permissions