Text: Clear glyph cache when it fills up

We can use a smaller glyph cache if we clear it when it fills up. Even a large cache would eventually fill up, so clearing is a good strategy anyway. Clears occur still rather infrequently.

# Conflicts:
#	src/ui/text.c

src/ui/text.c

@@ -369,7 +369,7 @@ static void initCache_Text_(iText *d) {
     init_Array(&d->cacheRows, sizeof(iCacheRow));
     const int textSize = d->contentFontSize * fontSize_UI;
     iAssert(textSize > 0);
-    const iInt2 cacheDims = init_I2(16, 80);
+    const iInt2 cacheDims = init_I2(16, 40);
     d->cacheSize = mul_I2(cacheDims, init1_I2(iMax(textSize, fontSize_UI)));
     SDL_RendererInfo renderInfo;
     SDL_GetRendererInfo(d->render, &renderInfo);

src/ui/window.c

@@ -960,7 +960,7 @@ void draw_Window(iWindow *d) {
 #if 0
     /* Text cache debugging. */ {
         SDL_Texture *cache = glyphCache_Text();
-        SDL_Rect rect = { d->root->rect.size.x - 640, 0, 640, 5 * 640 };
+        SDL_Rect rect = { d->root->rect.size.x - 640, 0, 640, 2.5 * 640 };
         SDL_SetRenderDrawColor(d->render, 0, 0, 0, 255);
         SDL_RenderFillRect(d->render, &rect);
         SDL_RenderCopy(d->render, glyphCache_Text(), NULL, &rect);