Added priority to also count inside files

[Licenser]

This is a extension of the file order patch. It extends the priority system to within files with the following rules:

The first element of a file has the highest priority, the last element has the lowest one (namely 0). Also mappings can get a {priority, X} setting passed that overwrites this automatic rule to force a mapping to have a specific position inside a file, this comes in handy to decouple position in the generated .conf file from the priority of a setting withn a file.

In file priorities take a lower impact then the permissions assigned by the file order, this prevent schema orders to mess with other schemas. (i.e. everything in 00.schema will always have a higher priority then 01.schema).

WARNING

This breaks some of the current behavior as it seems that as of this moment the last element in .schema to have the highest priority. I left the test failing to point this out.

Other then that I think the new behavior is more sensible since in other places the 'first has higher priority' is already working this way (i.e. the 00.schema lads first in the .config etc.)

[Licenser]

Adding as a note here not sure this is good or worth doing but I wanted to put it in for discussion ;)

[joedevivo]

Didn't want to include data that applied to the whole schema in the file. a schema file is intended to be a set of mappings, translations and validators.