1375 bugs in pattern syntax - #1378

1. Changes the pattern syntax to allow any EQName to be used for function calls; the constraints on which functions can be called are defined outside the actual grammar.
2. Reinstate root() as a permitted function
3. Allow doc()/id() without requiring parentheses around the second function call
4. Stylesheet changes to point external spec references at the 4.0 specs rather than 3.0.

Fix #1375