fix($compile): make order directives w/ same priority deterministic

Array.prototype.sort is speced out to be as potentionally unstable sort,
which is how it's implemented in FF and IE. This has caused the order
of directives with the same priority to vary between browsers.

For consistency sake, we now consider directive name and registration,
order when determining the order of directives with the same priority.

Note: it is still possible to get into a situation when the directive
order is underministic - when source files are loaded asynchronously
in non-deterministic order and there are are directives registered
with the same name and priority, the order in which they will be applied
will depend on the file load order.