Some iOS fixes to make SampleApp work better.

Changes:
- Rebuild argc and argv so we can process command line arguments
- Remove unnecessary SimpleiOSApp files
- Add support for reading files from the app bundle
- Add gpu flag so we can start up directly into OpenGL

Review URL: https://codereview.chromium.org/1382943004
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 02c5e03..c891508 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -711,6 +711,7 @@
 DEFINE_string(picture, "", "Path to single picture.");
 DEFINE_bool(sort, false, "Sort samples by title.");
 DEFINE_bool(list, false, "List samples?");
+DEFINE_bool(gpu, false, "Start up with gpu?");
 DEFINE_string(key, "", "");  // dummy to enable gm tests that have platform-specific names
 #ifdef SAMPLE_PDF_FILE_VIEWER
 DEFINE_string(pdfPath, "", "Path to direcotry of pdf files.");
@@ -799,6 +800,9 @@
 #endif
 
     fDeviceType = kRaster_DeviceType;
+    if (FLAGS_gpu) {
+        fDeviceType = kGPU_DeviceType;
+    }
 
 #if DEFAULT_TO_GPU
     fDeviceType = kGPU_DeviceType;