Update building.md
Add blank power issues page
Add hardware index page
Add SD Card Issues page
Add USB Issues page
Merge pull request #60 from toomuchatonce/patch-1

Update building.md
Update cmdline parameter in config.txt docs
Change wording Usage -> Usage Guide & reword description
Update CM docs structure, add schmeatics in the right place
Add Mathematica usage, close #59
Add missing Mathematica images
Crop 3d plot image
Usage folder restructure and tidy up
Move GPIO images to image folder
Add fractal picture to demo index page
Rename hello triangle 2 -> hello fractal
Fix broken camera link
Add WordPress logo
Add php & mysql logos
typos