[BUGFIX] Re-add link_spec JS function

[fnagel]

Needed for TYPO3 7.4 to fix RTE link browser.

Fixes #11

[fsuter]

I tried your patch, but I stumble on other issues. When clicking on the name of news folder (for example), I get a JS error complaining that function "insertElement" is undefined. And if I try to click on the expand arrow on the left side or the "drill in" arrow on the right side, I get the full BE loaded in the browse link popup. Did you not observe something similar? I'm actually not strictly on 7.4, but on 7.5-dev.

I'm willing to merge your pull request blindly, but it seems like more compatibility issues are ahead. I must admit that I'm getting rather desperate. I hope that this effort makes it: https://forge.typo3.org/issues/46140

[fnagel]

Just tested this again in 7.4.0 and it seems everything works fine. No JS errors, no wrong reloading. Using latest Chrome on Win8.1.

Sounds like you're right and something bad will happen in 7.5.

[fsuter]

Thanks for your feedback. So I went ahead and merged your change. Let's see if we can manage to keep that patient's heart beating :-\