Qt buildfix for Qt 5.2.0

adding the -lz in line "LIBS" in Linux section to fix compilation error when compiling under Qt version 5.2.0. See issue #4885
Added ShortcutActivity class to respond to homescreen shortcut intent.
It will show file dialog and return path to selected file as intent response.
Added simple file chooser dialog,
This is to select game iso when creating homescreen shortcut.

Probably not an ideal solution, could use ppsspp internal GameBrowser later.
Added name to display when user long-press homescreen and choose "Shortcuts".
In our case it's "PPSSPP game".
Added ShortcutActivity class on ppsspp manifest, so it will appears on homescreen shortcuts choice ("PPSSPP game" in our case).
- Moved SHORTCUT_EXTRA_KEY and shortcut query here.

- Call super.setShortcutParam(getIntent().getStringExtra(SHORTCUT_EXTRA_KEY))
before super.onCreate()
- Change SHORTCUT_EXTRA_KEY reference from NativeActivity to PpssppActivity.
Update native
Merge pull request #5023 from valef/android-shortcut

Android homescreen shortcut
Enable depth buffer copies on GLES3 devices without breaking any desktop
Symbian buildfix
Prevent the accelerometer from being mapped to controls directly until we can create sane UI for that.
Also disable some weird axis events we get on Ouya from mapping.
Prevent function replacer from replacing asinf and acosf, they seem to have colliding hashes in some games
"Next Slot" control mapping

-added "Next Slot" to control mapping menu
-added VIRTKEY_NEXT_SLOT -> incremented VIRTKEY_TOGGLE_FULLSCREEN
-added SaveState::NextSlot(); as replacement for code in
WndMainWindow
-added entry in EmuScreen using SaveState::NextSlot();
Win32: Add option to disable the Windows key.
Add a comment for the keyboard hook.
Let's be consistent with our spacing and if's.
Win32: Add the option to the Game Settings menu, too, and add a separator in NewUI.
Fix corrupted frames in Dainiji_Super_Robot_Taisen_Z_Hakaihen