Tessellation partial implementation (not ready for use yet), including:

- the built-in constants
 - built-in variable declarations, some dependent on gl_MaxPatchVertices
 - layout qualifier for vertices (shared with geometry shader max_vertices)
 - layout qualifiers for vertex spacing, vertex order, point mode, and primitive type
 - link semantics for layout qualifiers

Still TBD:
 - patch qualifier and arrayed input handling
 - sizing of gl_out[]
 - additional semantic checking
 - supporting the extension on version 150

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@24468 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/baseResults/420.tese.out

@@ -16,6 +16,9 @@ ERROR: 0:58: 'initializer list' : wrong number of structure members
 ERROR: 13 compilation errors.  No code generated.
 
 
+input primitive = none
+vertex spacing = none
+triangle order = none
 ERROR: node is still EOpNull!
 0:4  Sequence
 0:4    move second child to first child (2X2 matrix of float)
@@ -160,5 +163,9 @@ ERROR: node is still EOpNull!
 
 Linked tessellation evaluation stage:
 
+ERROR: Linking tessellation evaluation stage: At least one tessellation shader must specify an input layout primitive
 
+input primitive = none
+vertex spacing = equal_spacing
+triangle order = ccw