Support building for linux and ARM (#16)

* Added build jobs for all Windows platforms

* Added linux builds

* Added toolchain file for ARM soft-float

buildsystem/toolchains/arm-linux-gnueabi.cmake

@@ -0,0 +1,13 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR arm)
+
+set(CMAKE_C_COMPILER /usr/bin/arm-linux-gnueabi-gcc)
+set(CMAKE_CXX_COMPILER /usr/bin/arm-linux-gnueabi-g++)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)