zip release unzips into pwd, not own dir

[returnthis]

unzipping the release should create a single dir in the pwd. It should not unzip into the current dir.

Expected:

$ cd ~/temp
$ wget http://jquery.com/src/jquery-1.1.2.build.zip
$ unzip jquery-1.1.2.build.zip

there should now be a ~/temp/jquery-1.1.2 dir

However, the current zip files all uncompress into the cur dir.

[joern]

Fixed in [4487] for plugins.