replace previous arbitrary call to contentChanged that widgets were relying on during initialization for overloaded behaviors

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
ensure that we don't propagate invalid values to the style tag

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
for componentOverrides it needs to not stomp on the observers of the base kind

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
inline note to designate a previous misconception

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
Merge pull request #731 from enyojs/2.5.0-bulk-fixes

Fix for: BHV-8483 & BHV-8471

Reviewed-by: Aaron Tam (aaron.tam@lge.com)
ensure that style is properly removed as expected when nullified
account for removed auto call to srcChanged in Control
Merge pull request #732 from enyojs/BHV-8478-coledavis

Fix for: BHV-8478
adjust classes api to properly match previous expected behaviors

Enyo-DCO-1.1-Signed-Off-By: Cole Davis (cole.davis@lge.com)
Merge pull request #733 from enyojs/BHV-8478-coledavis

Fix for: BHV-8478