use only default https ports for https check

Deprecates RetryableStatusCodeException 

spring boot uses all high ports and there are some trouble if ports end with 443 (e.g. 24443, ...)

see gh-1950

Let SecurityContextConcurrencyStrategy be installed as the hystrix
concurrency strategy regardless of if feign's hystrix support is installed.

fixes gh-1969

fixes gh-1795

The timeToLive and timeUnit parameters added to configure connection pool.

Fixes gh-1720

fixes gh-1956

fixes gh-1955

Fixes gh-1598

Fixes a race condition introduced in 1.3.0

fixes gh-1933

Add @Component for Feign Hystrix Fallback example in doc

Add support for Wildcard Types in Feign Client.  Fixes gh-1676

change HttpServletResponse to HttpServletRequest

polish FeignLoadBalancer, remove unused import statement