Adding missing 'drop_index' and 'index_information' collection methods

Adding missing 'drop_index' and 'index_information' collection methods
+ adding tests
Adding the missing 'with_limit_and_skip' parameter for count - fixing #98
Revert "Adding the missing 'with_limit_and_skip' parameter for count - fixing #98"

This reverts commit 4eb8e3c8dec7d15ba57bfcd93184b0d3b19e0940.
Merge pull request #100 from baruchoxman/master

Adding missing 'drop_index' and 'index_information' collection methods - fixing #99