Merge pull request #3 from manasij7479/master

const ness updates in base class, etc
Void has no address.
ValueExtractionSynthesizer: check for the existance and accessibility of copy constructor. (ROOT-6185).
Default cling::Value set to invalid.

The cling::Value is initialized to be invalid then the value extraction changes it or not. If we do not have an available copy constructor for objects the value stays invalid.
Value extraction setting void types.

In the case the type is void we have to reset the maybe different object type pushed on the stack before the assesment of the desugared type.
Correct line alignment.
Value extraction: not a record decl we have copy ctor by default.
Wrap using decl/def that are followed by code (ROOT-6153).
If we don't have the information about the type of the RHS report an and exit.
Fix value printing for functions. Needs test!
Add support for .@ to cancel continuation
Add missing transaction in Interpreter::StateDebuggerRAII::StateDebuggerRAII

This prevents .printDebug from crashing.  However it is still more verbose
than expected.
Add missing transaction in Interpreter::StateDebuggerRAII::~StateDebuggerRAII

This prevents .printDebug from crashing.  However it is still more verbose
than expected.
Add a description and further resources for reading.
For backward compatiblity (for example with Proof), re-add support for .include
Merge branch 'master' of https://root.cern.ch/git/cling

Conflicts:
	lib/MetaProcessor/MetaParser.cpp
Merge remote-tracking branch 'upstream/master'
added some stl forward decls