added davix-0.2.8 support, which is now also supported on OSX.
ignore interpreter/cling/lib/Interpreter/cling-compiledata.h.
use libDavix by default if found by ./configure.
Add a flag in the system.rootrc - if lines/polygons should be anti-aliased

- with anti-aliasing on non-retina displays lines look thick and semi-transparent.
Give a choice - if user wants them to look more "X11-like" (version with XQuartz).
Fill TDataMember attribute map starting from an XML selection file.

The mechanism followed is the previous one:
1) Add metadata to the selection rule (of the class or of the field)
2) Add it to the ast in rootcling in form of attribute
3) Read it in TMetaUtils and fill the proper TDictAttributeMap
Adopt coding convention for include guards (thanks Fons)

and profit to add some documentation in the code.
Fix the output location of the rootmap files and pch files (CMake)
Fix a bug found in debug mode (== very slow startup) - no need

in scrolling animation at all - it must only work if 'About' was chosen.