[3.0] Fix native image capture code and DALi image saving

[3.0] Fix native image capture code and DALi image saving

1.
When trying to save an Image using
NativeImageSource::EncodeToFile( )
it was found that the JPEG and PNG code for saving a file had a bug
resulting in zero byte files being created.

Cause of the problem was due to code using Vector::Reserve
then a memcpy to copy image data into a vector. The vector
was then passed to function to save. As Vector::Reserve
doesn't adjust the size of the vector, Vector::Count()
was returning zero, so zero bytes were being written.

2.
When converting pixel data from TBM_FORMAT_RGB888 and
TBM_FORMAT_RGBA8888 to Dali::Pixel::RGB888 and Pixel::RGB8888
the Red component of a pixel was never being set
 ( except with an incorrect value for the first pixel of every line).

This resulted in captured images being green/blue.

Change-Id: Ie24d50a5f25449a78623a9b91eb68a52843a179b