Rename mget to []

- In sets, tables, strtabs, critbits, xmltree
- This uses the new var parameter overloading
- mget variants still exist, but are deprecated in favor of `[]`
- Includes tests and fixed tests and usages of mget
- The non-var `[]` now throws an exception instead of returning binary 0
  or an empty string

tests/misc/teventemitter.nim

@@ -13,21 +13,20 @@ proc emit*(emitter: EventEmitter, event: string, args: EventArgs) =
   for fn in nodes(emitter.events[event]):
     fn.value(args) #call function with args.
 
-proc on*(emitter: var EventEmitter, event: string, 
+proc on*(emitter: var EventEmitter, event: string,
          fn: proc(e: EventArgs) {.nimcall.}) =
   if not hasKey(emitter.events, event):
     var list: DoublyLinkedList[proc(e: EventArgs) {.nimcall.}]
     add(emitter.events, event, list) #if not, add it.
-  append(emitter.events.mget(event), fn)
+  append(emitter.events[event], fn)
 
 proc initEmitter(emitter: var EventEmitter) =
-  emitter.events = initTable[string, 
+  emitter.events = initTable[string,
     DoublyLinkedList[proc(e: EventArgs) {.nimcall.}]]()
 
-var 
+var
   ee: EventEmitter
   args: EventArgs
 initEmitter(ee)
 ee.on("print", proc(e: EventArgs) = echo("pie"))
 ee.emit("print", args)
-