Add IBM Text to Speech API

Updated CONTRIBUTING.md

The Text to Speech service processes text and natural language to generate synthesized audio output complete with appropriate cadence and intonation.
More info on https://console.bluemix.net/catalog/services/text-to-speech

Remove Kairos Api

Kairos remove free plan

Added SoundCloud API

Update README.md

Typo fix

Removed Certly

Updated Clearbit Logo auth

Reason: Website does not work anymore

* Adding CalendarIndex Holidays API

* Removing . from the end of the description

* Remove "API" from Description

Fix casing of GitHub "h"

This is a nitpicking thing but GitHub is spelled with a capital H.

* Add Nager.Date Public holiday project with api

* Update README.md

Closes #758

Combining PRs #728 and #741.

* crypto apis

* tick fixes

* chasing coins api

* Added CoinLayer API

* Fixed CoinLayer description

* Fixed description

* Add trash nothing

* Remove exclamation point

* Title case

* Adds Bored API

* Removes "API" from title

* Update README.md

Added currents api to available list

* Forum to plural

Fixes Issue #730

GDAX is being replaced/rebranded as Coinbase Pro

* crypto apis

* tick fixes

* bitcoinAverage API

Update Photography APIs

Update README.md

Fixes Issue #736 

For reference: https://open.fda.gov/about/updates/2018_06_22_new_look_same_great_api

Typo in README