Fix race condition in clearing leaked controls.
Fix some uninitialized variables discovered using valgrind.
Don't change the scaler if it is over-ridden for testing.
Only force vinyl mode to absolute on seek if the deck is playing.
Add compiler_is_gcc and compiler_is_clang variables to build object.
Add Clang-based features: address sanitizer and color diagnostics.
Remove unused BPMSCHEME_FILE and TRACK_FILE defines.
Turn headerpad settings into a proper linker-only command.

Clang complains it is not a valid compiler flag.
Add WComboBox, a QComboBox-derived WBaseWidget.
Reduce duplication in LegacySkinParser using some template methods.
Add WSplitter so that we can stop putting QSplitter in our style sheets (in case we want to replace it with a custom widget at some point in the future).
Use the right parent class for QWidget::event.
Merge branch 'master' into features_effects

Conflicts:
	src/skin/legacyskinparser.h
Reduce effect name widget duplication with setupLabelWidget.
Set parameter slot control default values so that reset works properly.
Merge pull request #5 from ywwg/rryan-features_effects

Small tweaks to echo effect.
Add description to EffectChain.
Show description in tooltip for WEffectChain, WEffect, and WEffectParameter.
Add GroupEffectProcessor, a helper class for defining effects with automatic
group-state creation.
Convert all native effects to use GroupEffectProcessor.