removed ROOT dependencies from utils library

- changed TMath function calls to matching ones in math.h and cmath in PixUtil
- removed include of TH1.h from PixTestParameters that is obsolete since 2a1fc1609559dee8986e284c449352fdd9c685e6
- addresses issue psi46/pxar#94
fixed GCC warning in ConfigParameters due to unused variable
made ROOT dictionary generation optional for util library

- will only be generated if CMake variable BUILD_pxarui is set to true
- addresses issue psi46/pxar#94
build utils library separately (BUILD_utils) and remove ROOT dependency/dictionary generation

-addresses issues psi46/pxar#94, psi46/pxar#98, psi46/pxar#20, psi46/pxar#105
Merge pull request #108 from hperrey/rootless_utils

Build utils library without ROOT