Added symbolic link "aerospike" to current directory.

This makes it possible to use:
```go
import "github.com/aerospike/aerospike-client-go/aerospike"
```
as required by some Go-IDEs (among which IntelliJ) - the package name should be the same as the directory name they are in (according to those IDEs)

This way, we still follow the Go-guidelines at: https://golang.org/doc/code.html#Workspaces
I quote: "src contains Go source files organized into packages (one package per directory)"

According to the Godoc documentation, symlinks are completely ignored as to the godoc.org webpage, so no issues there. 

The symbolic link (named "aerospike") points to its current directory (with all the .go files inside).