Several Gdx.Net enhancements.
Small changes.
Merge branch 'master' of https://github.com/libgdx/libgdx into netstuff
Added note to CHANGES.
BASIC ios vibrate, boo apple
Removed the new HTTP methods.
Emulate BufferUtils.copy(Buffer, Buffer, numElements)
Merge pull request #2467 from nooone/netstuff

Small improvements for Gdx.Net (HTTP)
Merge pull request #2506 from xoppa/bufferutils

Emulate BufferUtils.copy(Buffer, Buffer, numElements)
Merge pull request #2499 from Tom-Ski/vibrate

BASIC ios vibrate, boo apple
Add support for converting popular Android ARGB8888 format

As requested, replaces PR #2410 with a clean change history.

In a recent code review, I found two versions of this function in my code, so I thought it might be a useful addition. My code originally was Android-only before porting to libGDX, so perhaps others will be in this same situation and will find it convenient.
Merge pull request #2507 from mikemee/master

Add support for converting popular Android ARGB8888 format
Add variant of argb8888 method taking components
New PNG encoder that supports compression, more efficient vertical flipping, and minimal allocation when encoding multiple PNGs.

closes #2501
Fixed PNG encoder for all pixmap formats.

#2501
Fixes #2512