- fix xlsx file extension
- load from CDN where possible (currently not for webshim)
- make frontpage a bit more inviting to new users
renamed a lot of items.
improved show if behaviour - currently it can only be tested within runs though.
found annoying excel behaviour: false and true are special values, fortunately PHP excel just casts them as PHP types and PHP is sucky but this is something I by know how to work aroud
Merge branch 'release/v0.4.1' into develop