Add support for calling functions from UI (functions specified in XML).

[gemarcano]

I think we forgot about this.

[ajl2612]

Functions should be a string that can be executed from bash as well as a group of arguments. Arguments should be fields similar to the rest of the UI. There should also be a button on the UI to execute said function.

[ajl2612]

Enums in XML, change value field to name. Add attribute to field named value to hold int. One final element with one of previously defined enum values to initialize server to.