Env variable "MICROHTTPD_ROOT" is ignored by cmake

Fixing bug in CMakeLists.txt preventing to pick up microhttpd library root as defined in environment variable "MICROHTTPD_ROOT"
Example: "export MICROHTTPD_ROOT=/opt/gnu/libmicrohttpd-0.9.55" will be ignored without this fix

Fixes README.md typo

Just deleted repeated word :)

build_xmr-stak_docker script improved

fix typos in config.txt

Race condition fix

Build documentation improved and added "docker script" for building xmr-stak for other distributions

Typo Fix

merge master back to dev

use precompiled dependencies

- update appveyor CI
- update `WINCOMPILE.md` guide

Fix `Lare` -> `Large`

fix appveyor tests

disable OpenSSL to pass the CI

Installation steps for Ubuntu 14.04 added

Update default pools

Topic bug squashing

Initial JSON API implementation

Compile cleanup