New default values for PSOL options #721

Our experience with PSOL and Pagespeed Service indicates that the default 
values for certain options should change:

DefaultCssImageInlineMaxBytes = 0 (was 2048)
DefaultImageInlineMaxBytes = 3072 (was 2048)
DefaultMinImageSizeLowResolutionBytes = 3072 (was 1024)
AvoidRenamingIntrospectiveJavascript: true
DefaultMaxInlinedPreviewImagesIndex = -1 (was 5)

All of these were -1 (lossless):
DefaultImageRecompressQuality = 85
DefaultImageJpegRecompressQualityForSmallScreens = 70
DefaultImageWebpRecompressQuality = 80
DefaultImageWebpRecompressQualityForSmallScreens = 70

This will result in the use of lossy compression for images in future, 
resulting in dramatic reductions in image size with little loss in perceptible 
image quality in virtually every case.  (With a bit more risk, site owners can 
reduce these values further.)