Modify depends for monero's dependencies

Add readline, ldns, graphviz, unbound to depends packages

Add a cmake toolchain file to depends that is uniquely created for every build and placed in triple/share/toolchain.cmake
This file is then passed to cmake with -DCMAKE_TOOLCHAIN_FILE=/path/to/triple/share/toolchain.cmake

Add the boost locale package to depends

In the depends cmake toolchain file, a DEPENDS flag is added
to exclude, or change cmake checks done that are required for depends

Link miniupnpc and unwind from depends and not external

Add libiconv and icu4c to depends, required for mingw32 builds.

Headers (winsock) need to be lower case in order to compile on unix systems.
This should not affect building on windows.

contrib/depends/packages/cmake/test/CMakeLists.txt

@@ -0,0 +1,18 @@
+# This file is part of MXE. See LICENSE.md for licensing information.
+
+# 2.8.9 is Debian Wheezy version
+cmake_minimum_required(VERSION 2.8.9)
+
+# use default C and CXX languages
+project(mxe)
+
+# see cmake --help-policy <cmp> for details
+cmake_policy(SET CMP0017 NEW)
+if (POLICY CMP0020)
+    cmake_policy(SET CMP0020 NEW)
+endif()
+
+# so we can find pkg-test.cmake files to include
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/../.. ${CMAKE_MODULE_PATH})
+
+include(${PKG}-test)