Update dev dependencies

We have a few outdated dev dependencies in master atm. Specifically:

grunt-karma (package: ^0.8.2, latest: 0.9.0)
grunt-concat-sourcemap (package: ^0.4.1, latest: 0.4.3)
grunt-string-replace (package: ^0.2.7, latest: 1.0.0)
karma-ie-launcher (package: ^0.1.0, latest: 0.1.5)
karma-firefox-launcher (package: ^0.1.0, latest: 0.1.3)
karma-mocha (package: ^0.1.3, latest: 0.1.9)
grunt-contrib-uglify (package: ^0.5.0, latest: 0.6.0)
karma-safari-launcher (package: ^0.1.0, latest: 0.1.1)
grunt-contrib-concat (package: ^0.4.0, latest: 0.5.0)
karma (package: ^0.12.14, latest: 0.12.23)

This PR updates us to the latest versions of these packages.