More control over Permissions (re-written) + Security Improvements + Much more stable and coherent

Re-written permissions allow the setting of permissions for individual
functions, so you can block .set() and allow .update(), etc.

____

We’ve gone over Cenny.js to make sure that all requests follow a single
security standard.

.user.signin() has become more descriptive, and will stop an attempt to
sign into a user, if you are already signed into that user before a
request is made.

+++more improvements and bug fixes