Huge refactor regarding concurrency.

Now we have pooler which will pool connections (like pinging),
so there will be no timeouts due to "we have launched 100000 goroutines".

Reworked all code to use events (see Eventer). Still more work about
this to go.

Maybe more fixes I forgot.

requester/exported.go

@@ -12,9 +12,20 @@ package requester
 import (
     // stdlib
     "fmt"
+
+    // local
+    "github.com/pztrn/urtrator/cache"
+    "github.com/pztrn/urtrator/eventer"
 )
 
-func New() *Requester {
+var (
+    Cache *cache.Cache
+    Eventer *eventer.Eventer
+)
+
+func New(c *cache.Cache, e *eventer.Eventer) *Requester {
+    Cache = c
+    Eventer = e
     fmt.Println("Creating Requester object...")
     r := Requester{}
     return &r