Added error output to the preprocessor.

This patch distinguishes preprocessing errors with normal parsing
errors and gives glslangValidator the ability to output preprocessing
errors.

Test/baseResults/preprocessor.edge_cases.vert.err

@@ -0,0 +1,2 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+

Test/baseResults/preprocessor.errors.vert.err

@@ -0,0 +1,8 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+ERROR: 0:9: '#error' : This should show up in pp output .
+ERROR: 0:14: '#' : invalid directive: def
+ERROR: 0:15: 'preprocessor evaluation' : undefined macro in expression not allowed in es profile Y
+ERROR: 0:21: '' : missing #endif
+ERROR: 4 compilation errors. No code generated.
+
+

Test/baseResults/preprocessor.errors.vert.out

@@ -1,16 +0,0 @@
-#version 310 es
-
-
-
-
-
-
-
-#error This should show up in pp output . 
-
-
-
-
-int main(){
-}
-

Test/baseResults/preprocessor.extensions.vert.err

@@ -0,0 +1,4 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+WARNING: 0:5: '#extension' : extension is only partially supported: GL_EXT_gpu_shader5
+WARNING: 0:6: '#extension' : extension not supported: GL_EXT_shader_texture_image_samples
+

Test/baseResults/preprocessor.function_macro.vert.err

@@ -0,0 +1,2 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+

Test/baseResults/preprocessor.pragma.vert.err

@@ -0,0 +1,2 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+

Test/baseResults/preprocessor.simple.vert.err

@@ -0,0 +1,2 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+

Test/baseResults/preprocessor.success_if_parse_would_fail.vert.out

@@ -0,0 +1,4 @@
+int x(){
+  something that shouldnt compile;
+}
+