Fixes for issue #225 and #247

 - First pass works in limited testing.
- search() fix path (URL) to use 1.1 API url
 - search() allowed_param changes: rpp -> count, adding include_entities
 - search_api flag no longer needed or used.
 - SearchResults class: Pull list results from ['statuses'], use
  parse_datetime() rather than parse_search_datetime() since the date
  format is now standardized.
 - utils.parse_search_datetime() no longer used and has been deleted.
Adding search_metadata parsing and basic unit tests for search() method.
'page' is no longer a valid parameter for V1.1 search API.
Adding SearchResultsIterator for v1.1 API Cursor capability
search_host is no longer used with v1.1 API support.
Simplifying search() forward paging.
Fix typo in previous commit.
Move page limit test  (saves an extra invocation at end.)
Merge pull request #1 from leftronic/fix-v2-search

Fix v2 search