Prevent clearing label background when it's set.

I.e. prevent clearing `label.backgroundColor` when it's neither unset
nor white.
Add UIButton *-selected-highlighted states and missing text-shadow-color-disabled
Added a NUI-wide constants file and replaced the first ones
Replaced explicit class comparisons with 'isMemberOfClass'
Blending optimization for 'imageFromColorName conversion
Merge pull request #149 from benjie/patch-1

Prevent clearing label background when it's set.
Fixing an issue that causes a crash when an observer messages an object which has been deallocated.
Merge pull request #169 from mutualmobile/master

Fixing an issue that causes a crash when an observer messages an object ...
Version 0.3.5
Merge pull request #159 from mirego/add-button-selected-highlighted

Add UIButton *-selected-highlighted states
Merge pull request #164 from Hecktorzr/constants_replacement

Added a NUI-wide constants file and replaced the first ones
Merge pull request #165 from Hecktorzr/class_comparison

Replaced explicit class comparisons with 'isMemberOfClass'
Replaced 'applied flag' with simpler accessor
Included classes not inheriting from UIView in the BOOL flag refactor
Merge pull request #166 from Hecktorzr/nui_properties

Replaced 'applied flag' with simpler accessor
Version 0.4.0
Added newline to files not ending in newline.

... To prevent compiler warnings in projects that check for this.
Prevent warning in 64bit arch due to string format,
Fix variable shadowing warnings.
Merge pull request #167 from iOSCowboy/blending_improv

Blending optimization for 'imageFromColorName conversion