Update to reflect changes in Clang.
In Clang r178037, MacroDirective::getInfo was renamed getMacroInfo.

git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@461 812d1f90-f944-d88a-411a-122bdc93e1ea
Clean up includes for include_picker.h/cc.
No functional change.

git-svn-id: http://include-what-you-use.googlecode.com/svn/trunk@462 812d1f90-f944-d88a-411a-122bdc93e1ea