remove blue highlight on search box.

themes can still change ::focus styles via stylesheets so there is no usability loss.
remove blue highlight on library sidebar
Some minor tweaks to equalizer effect:

* Rename to Butterworth EQ (since Default is not very meaningful and unclear given
  we have two types of EQs).
* Fix memory leak.
* Get translations for parameter descriptions.
Rename EQDefault class to ButterworthEQEffect.
Create new appstore scons option for Mac App Store builds.

Disables the reverb effect and vinyl control, which are not available
with the App Store Exception.  Attempting to enable vinylcontrol=1
with appstore=1 will not succeed.
Merge pull request #266 from leematos/patch-2

Remove blue glow from searchbox & library sidebar
Ensure that Mac App Store build options are explicitly Mac-specific.
Merge pull request #289 from ywwg/mac-disable-reverb

Create new appstore scons option for Mac App Store builds.