Use glyph metrics for spacing.

The CharacterSpacing property of Font can be used to add additional spacing
between characters and is by default 0.
Use glyph metrics for white characters.
Increase GPB minor version because of changes in TTFGlyph.
Read and write array of TTFGlyph platform independently.
Fixed Vector4::operator< (properly)
proper slider marker position calculation (no jumping on touch)
UI: control's addition/removing/hiding makes parents dirty, autoSize doesn't count invisible controls
Merge pull request #1520 from prshreshtha/patch-4

Fixed Vector4::operator< (properly)
Merge pull request #1521 from reven86/next-clean

UI fixes
Merge pull request #1518 from michalsrb/next

Use glyph metrics for spacing.
Fix text rendering on non-integer x position.

Rendering at non-integer x position makes first character of every line
disappear. It is because the position gets rounded down to integer and later
compared against the original float. First character then seem to be out of
the text area.
Merge pull request #1526 from michalsrb/next

Fix text rendering on non-integer x position.
Fix leak in ParticleEmitter
Merge pull request #1531 from fallahn/next

Fix leak in ParticleEmitter
Fix TerrainPatch leaking camera
Fix typo in Sample Browser AndroidManifest.xml
Fix typo in PlatformAndroid.cpp - Fixes #1536
Add screenSize flag for android:configChanges

This stops the activity from being destroyed on lock screen on various
devices.

Fixes #1464
Merge pull request #1534 from fallahn/next

Fix TerrainPatch leaking camera
Merge pull request #1535 from rgngl/next

Fix typo in Sample Browser AndroidManifest.xml