Added vendor/ submodule.

Moved dependencies that need to be vendored into separate repository.
	- https://github.com/spdfg/elektron-vendor
Added vendor/ as a submodule using the below command.
	- git submodule add https://github.com/spdfg/elektron-vendor vendor
If wanting to use vendor, run the following commands after cloning
elektron.
1. git submodule init
2. git submodule update

vendor/.gitignore

@@ -0,0 +1,12 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out