[copy-server-files] `grunt serve` copy files

When initially running `yo web` and then `grunt serve`, the font files
are not copied and therefore, running localhost:9000 gets 404s when
trying to request the font files.  This runs the copy:server task
during `grunt serve` to resolve this issue.
Merge pull request #4 from danjamin/copy-server-files

fixed copy bootstrap fonts in `grunt serve`