This modifies jqPlot to support retina displays.

fixes #4389
rename class Filter -> BaseFilter to prevent error "two constructors are defined on PHP 5.3.2"
rename methods to prevent error "two constructors are defined on PHP 5.3.2"
fix Declaration of UIAssetCacheBusterMock::piwikVersionBasedCacheBuster() should be compatible with Piwik\AssetManager\UIAssetCacheBuster::piwikVersionBasedCacheBuster($pluginNames = false)
updated composer.lock as there is new jshrink lib
fix core tests
refs #4393 all websites appears in another line
refs #4393 reports added to the scheduled reports do not appear as checked. still looking for a better solution
fixes #4386 fix datepicker is not completely visible. I wanted to fix this in JS but unfortunately the beforeShow event of the datepicker is not working and I did not find any other workaround. So fixing it this way
make sure log class is loaded
Merge pull request #169 from piwik/fix-retina

Modify jqPlot to support retina displays.