Fix wrong accesses to Dimensions classes

 - change &obj to obj.getPointer()
 - reduce line lengths to about 80
Beautify cmake file
Dummy change to trigger new test
Continue fixing picongpu cmake file

 - add PIC_VT_ROOT_DIR variable
 - remove .s
 - remove sm_13 and check for unsupported compute capab.
Update other cmake files
Merge pull request #78 from f-schmitt-zih/fix-dimensions

Fix #70 dimensions
Fix CUDA_NVCC_FLAGS in cmake file
Merge pull request #79 from f-schmitt-zih/pretty-cmake

Beautify cmake file

- fix nvcc_tmp dir