[fix #48723465] Added comparison filter
[fix #48723465] ComparisonFilter can join to other filters
[fix #48723465] more comparison operator related tests
[fix #48723465] Removed unneeded 'model' parameter
Merge pull request #172 from ke4/48723465_add_comparison_filter_to_search

48723465 add comparison filter to search
[fix #48723465] Removed unneeded code
Merge pull request #173 from ke4/48723465_add_comparison_filter_to_search

[fix #48723465] Removed unneeded code