Preprocessor: Rationalize, simplify, and correct the stack of input sources and their tokenization. This included

- consistently dealing with EOF and its effect on error recovery (bug 11444, #1)
 - turning a simulated OO hierarchy of function pointers and typecasting into a real C++ class hierarchy
 - correctly handling '\' everywhere, in all classes of tokens, as a layer before preprocessing itself
 - conditionally handling '\n' in macro expansion input, depending on whether it is in a macro expression or not
 - delete some unused "memory cleanup" code


git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@24626 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/baseResults/cppNest.vert.out

@@ -3,7 +3,9 @@ ERROR: 0:144: '#elif' : #elif after #else
 ERROR: 0:152: '#else' : #else after #else 
 ERROR: 0:161: '#elif' : #elif after #else 
 ERROR: 0:169: '#else' : #else after #else 
-ERROR: 4 compilation errors.  No code generated.
+ERROR: 0:177: 'macro expansion' : EOF in macro FUNC
+ERROR: 0:178: '' :  syntax error
+ERROR: 6 compilation errors.  No code generated.
 
 
 ERROR: node is still EOpNull!
@@ -58,6 +60,11 @@ ERROR: node is still EOpNull!
 0:133      'selected3' (int)
 0:133      Constant:
 0:133        3 (const int)
+0:175  Function Definition: foo985( (void)
+0:175    Function Parameters: 
+0:175    Sequence
+0:175      Constant:
+0:175        6 (const int)
 0:?   Linker Objects
 0:?     'sum' (float)
 0:?     'selected4' (int)