cogl: improves header and coding style consistency

We've had complaints that our Cogl code/headers are a bit "special" so
this is a first pass at tidying things up by giving them some
consistency. These changes are all consistent with how new code in Cogl
is being written, but the style isn't consistently applied across all
code yet.

There are two parts to this patch; but since each one required a large
amount of effort to maintain tidy indenting it made sense to combine the
changes to reduce the time spent re indenting the same lines.

The first change is to use a consistent style for declaring function
prototypes in headers. Cogl headers now consistently use this style for
prototypes:

 return_type
 cogl_function_name (CoglType arg0,
                     CoglType arg1);

Not everyone likes this style, but it seems that most of the currently
active Cogl developers agree on it.

The second change is to constrain the use of redundant glib data types
in Cogl. Uses of gint, guint, gfloat, glong, gulong and gchar have all
been replaced with int, unsigned int, float, long, unsigned long and char
respectively. When talking about pixel data; use of guchar has been
replaced with guint8, otherwise unsigned char can be used.

The glib types that we continue to use for portability are gboolean,
gint{8,16,32,64}, guint{8,16,32,64} and gsize.

The general intention is that Cogl should look palatable to the widest
range of C programmers including those outside the Gnome community so
- especially for the public API - we want to minimize the number of
foreign looking typedefs.

cogl/cogl-vertex-buffer.c

@@ -210,7 +210,7 @@ COGL_HANDLE_DEFINE (VertexBuffer, vertex_buffer);
 COGL_HANDLE_DEFINE (VertexBufferIndices, vertex_buffer_indices);
 
 CoglHandle
-cogl_vertex_buffer_new (guint n_vertices)
+cogl_vertex_buffer_new (unsigned int n_vertices)
 {
   CoglVertexBuffer *buffer = g_slice_alloc (sizeof (CoglVertexBuffer));
 
@@ -223,7 +223,7 @@ cogl_vertex_buffer_new (guint n_vertices)
   return _cogl_vertex_buffer_handle_new (buffer);
 }
 
-guint
+unsigned int
 cogl_vertex_buffer_get_n_vertices (CoglHandle handle)
 {
   CoglVertexBuffer *buffer;
@@ -958,7 +958,7 @@ upload_multipack_vbo_via_map_buffer (CoglVertexBufferVBO *cogl_vbo)
 {
 #if HAVE_COGL_GL
   GList *tmp;
-  guint offset = 0;
+  unsigned int offset = 0;
   char *buf;
   gboolean fallback =
     (cogl_get_features () & COGL_FEATURE_VBOS) ? FALSE : TRUE;
@@ -1004,7 +1004,7 @@ static void
 upload_multipack_vbo_via_buffer_sub_data (CoglVertexBufferVBO *cogl_vbo)
 {
   GList *tmp;
-  guint offset = 0;
+  unsigned int offset = 0;
   gboolean fallback =
     (cogl_get_features () & COGL_FEATURE_VBOS) ? FALSE : TRUE;
 
@@ -1511,8 +1511,8 @@ enable_state_for_drawing_buffer (CoglVertexBuffer *buffer)
 #ifdef MAY_HAVE_PROGRAMABLE_GL
   GLuint       generic_index = 0;
 #endif
-  gulong       enable_flags = 0;
-  gint         max_texcoord_attrib_unit = -1;
+  unsigned long enable_flags = 0;
+  int          max_texcoord_attrib_unit = -1;
   const GList *layers;
   guint32      fallback_layers = 0;
   guint32      disable_layers = ~0;
@@ -1797,7 +1797,7 @@ cogl_vertex_buffer_indices_new (CoglIndicesType  indices_type,
 {
   gboolean fallback =
     (cogl_get_features () & COGL_FEATURE_VBOS) ? FALSE : TRUE;
-  size_t indices_bytes;
+  gsize indices_bytes;
   CoglVertexBufferIndices *indices;
 
   _COGL_GET_CONTEXT (ctx, 0);
@@ -1885,7 +1885,7 @@ cogl_vertex_buffer_draw_elements (CoglHandle       handle,
   CoglVertexBuffer *buffer;
   gboolean fallback =
     (cogl_get_features () & COGL_FEATURE_VBOS) ? FALSE : TRUE;
-  size_t byte_offset;
+  gsize byte_offset;
   CoglVertexBufferIndices *indices = NULL;
 
   _COGL_GET_CONTEXT (ctx, NO_RETVAL);
@@ -1936,7 +1936,7 @@ _cogl_vertex_buffer_free (CoglVertexBuffer *buffer)
 }
 
 CoglHandle
-cogl_vertex_buffer_indices_get_for_quads (guint n_indices)
+cogl_vertex_buffer_indices_get_for_quads (unsigned int n_indices)
 {
   _COGL_GET_CONTEXT (ctx, COGL_INVALID_HANDLE);