add random_indexes method
add select_random_current_version
optimize click_first_valid_signature
change test_that_selecting_exact_version to randomly select a version and check a subset of items for a signature.
change get_random_indexes method name
change click_first_non_empty_signature method name
change get_random_indexes method name
Remove mixed content test
remove unused mixed_content_warning property
Merge pull request #157 from zacc/remove_mixed_content_test

Remove mixed content test
Minor nit
Merge pull request #159 from AlinT/minor_nit

Minor nit
Merge pull request #158 from bebef1987/fix_versions

Add esr to version
Remove valid signature distinctions
Add explicit wait for jquery to complete when loading top crashers page
Merge pull request #161 from zacc/add_jquery_ajax_wait

Add explicit wait for jquery to complete when loading top crashers page
Merge pull request #160 from zacc/remove_empty_sig_methods

Remove valid signature distinctions
revert change to click_first_valid_signature
revert changes to first_valid_signature
changes following code review