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
Better way of specifying initial buffer size.
Merge remote-tracking branch 'origin/master'
Added renderObjects() to TiledMapRenderer
Merge pull request #2514 from Arcnor/master

Added renderObjects() to TiledMapRenderer
Removed IOException, reset pixel buffer position.
Merge remote-tracking branch 'origin/master'
Fixes #2517
Add MeshBuilderTest; normalTransform should be Matrix3; use color to tint specified vertex colors.
Use IntMap to store pointer against pointer UUID. Fixes #2516
Label#setEllipse -> Label#setEllipsis.

closes #2529
correct color scaling in vertex shader
Merge pull request #2528 from Tom-Ski/gwt

Use IntMap to store pointer against pointer UUID. Fixes #2516
Merge pull request #2530 from vmilea/alpha

correct color scaling in vertex shader
Add null check in BitmapFont#toString()

BitmapFont loaded from FreeTypeFontGenerator does not have a fontFile set.

Fixes #2510
Removed unnecessary code
Merge pull request #2533 from obigu/scaling

Removed unnecessary code
Add ability to save atlas from PixmapPacker

Closes #2381