Optimize SVGs

`chrome.svg`:
  * __before__: 7275
  * __after__: <del>3447</del> 3722 
  * __reduction__:  <del>3828 [52.62%]</del> 3553 [48.84%]

`chromium.svg`:
  * __before__: 10722
  * __after__:  <del>4362</del> 4847
  * __reduction__: <del>6360 [59.32%]</del> 5875 [54.79%]

`firefox.svg`:
  * __before__: 45185
  * __after__:  <del>34243</del> 40533
  * __reduction__: <del>10942 [24.22%]</del> 4652 [10.30%]

`ie.svg`:
  * __before__: 9877
  * __after__:  <del>5705</del> 6105
  * __reduction__: <del>4172 [42.23%]</del> 3772 [38.19%]

`opera.svg`:
  * __before__: 14890
  * __after__:  <del>13484</del> 14527
  * __reduction__: <del>1406 [9.44%]</del> 363 [2.44%]