add extract prevention support

prevent extraction of zip with something like

extract=false nx get-i
script opening the Nexus IT report index.xml

only supports OSX atm. Someone else can add support for their platform
Merge pull request #14 from peterlynch/extract-prevention-support

add extract prevention support to nx-get-i
Merge pull request #16 from peterlynch/nx-it-report

script for OSX to open the Nexus IT report index.xml
Add JSW configuration to restart Nexus on HUP signal
nx-install: Download and unpack/install plugins into Nexus
nx-install: Add ability to install local file
Merge remote-tracking branch 'upstream/master'