- Removed generate_android_toolchain, since version r21 AndroidNDK it's the toolchain
 - Removed external lib native_app_glue, provided by AndroidNDK

Actually, project just adds 50MB of ANGLE libraries not related to raylib.
Also reviewed UWP project to consume ANGLE from the NuGet package.

* added log warning for unsupported file extension for music stream

* updated error log message for music stream when file format isn't supported

- Added NULL return if the replacement string (`by`) is empty
- Reordered sanity checks since there's no need to initialize variables if the strings are invalid.

* Fixed offset check in GenImageFontAtlas

* Fixed code formatting to follow raylib notation rules

It seems there is some related issue on emscripten side... but I'll keep the icons here despite not displayed properly for the moment.

Errores fixes:
models.c,2843 Either the condition 'fileData!=NULL' is redundant or there is possible null pointer dereference: fileData.
raudio.c,805, 806, 807, 808, %d in format string (no. 2) requires 'int' but the argument type is 'unsigned int'.

* [cppcheck] Improvements in SaveStorageValue() in core.c

in file core.c cppcheck shows errors only in function SaveStorageValue():

* Common realloc mistake: 'fileData' nulled but not freed upon failure
* Memory pointed to by 'fileData' is freed twice.

Validation:
* Tested examples/core/core_storage_values.c
* Launched Unit Test for this function
* Rerun CPPCHECK afer fix

* [cppcheck] Change functions header to accept only positive position in files

Changes:
* Functions SaveStorageValue(), LoadStorageValue() (core.c)
* Functions LoadFileData(), SaveFileData() (utils.c)
* Headers in raylib.h

Validation:
* Tested examples/core/core_storage_values.c
* Launched Unit Test for these functions
* Rerun CPPCHECK afer fix

* Update ImageDraw*() functions to match arguments of Draw*()

Updated draw functions:
ImageDrawPixel()
ImageDrawPixelV()
ImageDrawCircle()
ImageDrawCircleV()
ImageDrawLine()
ImageDrawLineV()
ImageDrawRectangle()
ImageDrawRectangleV()
ImageDrawRectangleRec()

* [nodepadpp] Update Notepad++ ImageDraw defintions

This updates the Notepad++ definitions with the updated ImageDraw methods.

* [examples] Add ImageDraw calls to textures_image_drawing

* Update ImageDraw*() methods

This reverts commit 2528854664.

* Update compilation warning flags

Removed the -Wall flag that allow many warnings and added manually all the warning flags that don't generate warnings in the src/external folder.
Specifically, these are some of the flags reporting errors in src/external:

-Wmissing-prototypes
-Wunused-variable
-Wunused-value
-Wunused-parameter
-Wunused-function

* Uptade compilation flags in examples with missing -std=c99

I don't like this solution but well... let's use it for the moment...

* Android: Better track touch input returned from IsMouse*()

Switch to actually tracking touch input to use for "mouse" input rather
than the gestures system. The gesture system as an abstraction ontop of
raw touch input loses some information needed to map to "mouse"
input.

Before,
- IsMouseButtonReleased() triggers immediately after the initial touch
(because GESTURE_TAP activates immediately on touch) instead of waiting for the
touch to be released.
- IsMouseButtonUp() returns false, when it should just be the opposite
of IsMouseButtonDown().
- IsMouseButtonDown() returns true only after GESTURE_HOLD (which
activates after some period of time after GESTURE_TAP), when instead it
should just be true whenever there is touch input i.e. gesture !=
GESTURE_NONE or alternatively when any input is received on the screen.

After this PR, touches map closer to mouse input.
- IsMouseButtonReleased() triggers when touch is released (last frame
was touched, this frame not touched).
- IsMouseButtonUp() returns the opposite of IsMouseButtonDown()
- IsMouseButtonDown() is true when
(AMOTION_EVENT_ACTION_DOWN || AMOTION_EVENT_ACTION_MOVE) and false when
(AMOTION_EVENT_ACTION_UP)

* RPI: Include index check for RPI in GetTouchPosition()

We might want to customize this in feature for multi-config builds (e.g.
a Visual studio build with both Debug and Release configurations).

Output the variable value for user awareness.