Replace linktastic with simple ctypes

Linktastic calls the command line interpreter to do linking. This
solution calls the windows API directly. This is faster and cleaner, but
most important of all: it doesn't cause a command window to popup every
time a link is made. This popup asks window focus and thus interrupts a
movie you are watching!!

Hopefully this also works on non-windows systems. I am unable to test
this so please let me know :)
Put link and symlink in helpers