Updated README

Updated README adding visualization tool and tweaking index size

Refactored index management for saving the data

Merge pull request #3 from AlbertSuarez/fix-issue-1

Added [filterRemoteData] and [fullTextSearch] to Semantic drop down

Merge pull request #2 from AlbertSuarez/api_cache

Removed two badges that were not needed

Added an OpenSource badge to README

Removed two unneeded tests now that we have cache in place

Changed maximum cache age to 1 hour

Implemented cache to song/search

Implemented cache to similarity/by_content

Implemented cache to similarity/by_song

Implemented cache helper file

Added ExpiringDict as a requirement