Use svgmin.

Hi Bas,

This is the implementation of 'svgmin' - https://github.com/sindresorhus/grunt-svgmin - which compresses the svg files between the copy and the replace tasks.  The shrinkage is not that much, but hey, it is still shrinkage:

core before:

![2014-07-25 13_49_29-pix_core properties](https://cloud.githubusercontent.com/assets/1058419/3704842/70e2afe0-1418-11e4-90b0-e8e123c3bacc.png)

core after:

![2014-07-25 16_39_28-pix_core properties](https://cloud.githubusercontent.com/assets/1058419/3704835/5ae48678-1418-11e4-8e5d-4da268b64264.png)

plugins before:

![2014-07-25 16_45_32-pix_plugins properties](https://cloud.githubusercontent.com/assets/1058419/3704852/805c7e42-1418-11e4-849a-91931f7d8c13.png)

plugins after:

![2014-07-25 16_50_36-pix_plugins properties](https://cloud.githubusercontent.com/assets/1058419/3704864/8c9fe590-1418-11e4-878c-c01e478b0d1a.png)

Cheers,

Gareth