added ServiceContainer for APIs
added unirest dependency
Revert "added unirest dependency"

This reverts commit 18ee25e1ec812ad7d8fa76e93331c7e88faf9a0e.
re-added unirest dep
enable autodiscovery by default
removed hardcoded mashape keys
updated documentation

added section and page for service-container docs
use environment variable MASHAPE_KEY
added file-header
added test for manual service-registration
more descriptive testname
changed test-order, perform autodiscovery=off test first
removed app argument from serviceContainer
formatting, added hint for testing
fixed method
fixed test for discover
log onky in debug mode
splitted tests into dedicated files
moved documentation into single pages
changed link