Correct doxygen doc.
Remove extra transaction iteration.
Add test targets.
On MacOS 10.9 our clang will not find the stdlib. Use the XCode's clang instead.
Implement Interpreter's InclusionDirective() callback

InclusionDirective() callback tells us that an inclusion directive has been processed, allowing us to try to autoload classes using their header file name.
For example try to autoload TGClient (libGui) when seeing #include "TGClient.h"
This should prevent potential crash when executing macros using globals (e.g. gClient), with the following error:
ExecutionContext: use of undefined symbol 'gClient'!
Fix non-MacOS platform.mac_ver().
libc++ fixes, e.g. c_str() returns const_pointer.
Add libc++ name for std::string.
Fix const char * regexp.
Move IsStdClass to cling::utils::Analyze
Introduce Transform::Config::DropDefaultArg

Currently only implemented for the STL collection.

This could eventually be used to allow customization
of which default argument to strip and which class template.

For now, it is only used to prevent the addition of template
default template argument to the STL collection ... which
we would any strip.

This fixes the secondary issue in ROOT-6020 (one class template
instance having more than one corresponding TClass due to the
inconsistency in the normalization (not adding vs not stripping)
Fix compilation on Windows
Fix typo in doxygen doc
Be more verbose when unable to detect the stdlib version.
Adjust to the test with the correct vars.