Replaced declaration IgnoreFlags by GenerationKind. Added methods IsInternal and IsDeclared to declaration. Replaced IsGenerated = true by GeneratioKind = GeneratioKind.Internal. Deprecated Ignore, replace Ignore set by ExplicityIgnored, replace Ignore get by IsGenerated, IsInternal or IsDeclared.

Conflicts:
	src/Generator/Passes/CheckOperatorsOverloads.cs
Changed CS_IGNORE_GEN to set generation kind to internal.
Replaced usage of «IsGenerated with IsDeclared when handling with base classes and value types properties.
Fixed QualifiedIdentifier when QualifiedName is empty (case of namespaces)
Changed property fields generation kind to internal.
Added to macro pass CS_CONSTRAINT which can be use to constraint generic arguments.
Changed Driver.Diagnostics setter to public. Replaced TextDiagnosticPrinter Verbose field by Level.
Added CheckIgnoreProperty to AST/Utils.cs. Changed CheckIgnoreField to handle value class fields declared in linked assemblies.
Removed non generated headers from includes collected.
TypeIgnoreChecker now ignores declarations when GenerationKind == GenerationKind.None.
External declarations are now only marked as such when being generated.
Deprecated ExplicityIgnored use ExplicitlyIgnore(). Getting ExplicityIgnored and setting ExplicityIgnored to false don't make much sense anymore.

Conflicts:
	src/Generator/Passes/CheckOperatorsOverloads.cs