Add extra memory to virtual machine and add coverage report to gitignore.

.gitignore

@@ -14,3 +14,4 @@ vendor
 test/p2p/data/
 test/logs
 .glide
+coverage.txt

Vagrantfile

@@ -5,7 +5,7 @@ Vagrant.configure("2") do |config|
   config.vm.box = "ubuntu/trusty64"
 
   config.vm.provider "virtualbox" do |v|
-    v.memory = 3072
+    v.memory = 4096
     v.cpus = 2
   end