SMILI Release Candidate 1

This version fixes a couple of issues on Windows on Mac platforms.

- Screenshot crash in sMILX has been fixed. Caused by offscreen rendering not working sometimes for Windows and Mac.
- Fixed Windows crash for vector images. Appears to have been caused by ITK 4.7. Upgraded to ITK 4.8.2.

Registration plugin has issues on Windows (DLL link error caused by the installer). A USB-stick version of SMILI will be provided shortly to allow users to use the plugin on Windows (marked '-Reg'). Ubuntu versions are unaffected.

Plugins are currently not being shipped in the Mac installers, as there are issues with the DragNDrop creator not working properly (with the current SMILI configuration) and this causes link errors. This will hopefully be fixed in the next release.