search for linux backend plugins

- search for plugin in
  - working directory
  - binary directory
  - let linux search the plugins (libraries)

OSX file file extension (dynamic libraries)

fix OSX compile

fix `/usr/bin/ld: bin/libxmr-stak-backend.a(jconf.cpp.o): relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC`

use `.dylib` as dynamic library file extension

- link `xmr-stak-backend` to `xmrstak_cuda_backend` to solve missing symboles

tune VEGA auto suggestion

add option: flush stdout

appveyor CUDA support

Added the option to forcefully flush STDOUT, which may be useful when running the miner through a pipe instead than a shell.
If STDOUT is a shell, it's unbuffered by default.
If STDOUT is a pipe, it's buffered by default.

- install CUDA
- compile miner with CUDA and OpenCL

- fix windows linker error during compile
- fix wrong parameter to call aeon (nvidia-backend)

increase safety memory for autosuggestion

- allow to use up to 2024 threads on VEGA gpus

fix #5

- increase safty memory from 64 to 128 MiB
- NVIDIA: increase lmem reserve per thread to 1kiB

add Aeon support

- fix that currency selection is not called (in cli-miner.cpp)
- fix guard to prevent wrong currency selection if compiled for monero or aeon only

- rename all `xmr` to `monero`
- be insensitive while check for set currency
- add function to compate two strings insensitive

- update auto suggestion default and hwloc
- extent hash function table to support aeon and xmr within one miner

- add template parameter to kernel to support aeon and xmr
- update auto suggestion

- add compile parameter to support aeon and xmr
- update auto suggestion to handle aeon

... into a single place

- cli-miner.hpp:
  - add option `--currency`
  - add guided start section
- config.tpl: add value `currency`
- params.hpp: add value to store the selected currency
- executor.hpp: add dev pool address

- add CMake flag description
- announce Monero and Aeon in README.md
i add FAQ section

thread affinity for non cpu backends

- check if affinity vale before calling `thd_setaffinity`

amd: use 64bit target

This is a follow up of #43 and use the some mechanism to set the thread affinity for
non cpu backends correct.

- use cpu affinity workflow for nvidia and amd
- cpu: move messages of thread spawning before thread creation

- remove 32bit target value
- use always 64bit target for amd backend

remove double blob copy

- remove double copied memory

prefere AMD OpenCL over NVIDIA, Intel

Implement pool-controlled nonce allocation

fix #56

Search for AMD OpenCL inlcude path and libaries to prioritize the AMD implementation over NVIDIA and Intel.

Proper removal of gpu_thread_num

fix illegal memory access