Update documentation and specs to reflect 100 ID limit

Closes #425.
Fix Twitter::SearchResults#rpp return value
Merge pull request #427 from ahmadsherif/master

Fix Twitter::SearchResults#rpp return value
Fix typos in documentation
Allow user to pass a Tweet ID, URI, or object

Suggested by @dianakimball :heart:
Replace Array, Set, etc. with Enumerable in documentation [ci skip]
Allow user to pass a Tweet IDs, URIs, or objects
Allow URIs everywhere
Use double-quotes consistently throughout specs
Allow URI strings in addition to URI objects
Reorder by number of commits instead of chronology [ci skip]

https://github.com/sferik/twitter/graphs/contributors
Implement Twitter::Cursor#each without making an extra HTTP request
Remove Twitter::Cursor#all
Remove Twitter::Cursor#collection
Implement collection caching
Start preparing README for version 5 [ci skip]
Make Twitter::SearchResults enumerable
Revert "Delegate Tweet#profile_image_url and Tweet#profile_image_url_https to Tweet#user"

This reverts commit 7bd6f8f589a91a8c82363d07da77ec012890c6cb.
Remove Twitter#from_user
Memoize result within Twitter::Base#new_or_null_object