Beach and Orchard metatile alignments

Providing a fix for #299 this changes the symbols for beach and orchard.

To maintain pixel-crispiness while bending to the Power of Two the density of the pebbles
has been reduced from 4+1 pixels to 7+1 pixels. 

This follows the opinion in fixing the allotments in #770, where the wider style was accepted as
adding more clarity to the map. 

New tiles:
![beachtile_687526](https://cloud.githubusercontent.com/assets/8266355/4293648/4c92cf50-3dd8-11e4-8633-fcff80d607b3.png)
![orchardtile_21538](https://cloud.githubusercontent.com/assets/8266355/4293649/4c973784-3dd8-11e4-8e73-a6c5f7e59a55.png)

Examples of current metatile artefacts:
http://www.openstreetmap.org/#map=18/52.37324/12.87641