Add proper virtual destructor to FlagBase.
Weyland will now compile and run the build file.

Also add exception handling, and assertions to main and the
commandline parser.

This should resolve surtrstudios/weyland#4
Fix syntax error in simple.js
Merge pull request #14 from smkell/development

Weyland now compiles and runs the build file.
Merge pull request #15 from surtrstudios/development

Prepare fix for surtrstudios/weyland#4 for release.