Make the Solidity repository standalone.

This commit is the culmination of several months of work to decouple Solidity from the webthree-umbrella so that it can be developed in parallel with cpp-ethereum (the Ethereum C++ runtime) and so that even for the Solidity unit-tests there is no hard-dependency onto the C++ runtime.

The Tests-over-IPC refactoring was a major step in the same process which was already committed.

This commit contains the following changes:

- A subset of the CMake functionality in webthree-helpers was extracted and tailored for Solidity into ./cmake.   Further cleanup is certainly possible.
- A subset of the libdevcore functionality in libweb3core was extracted and tailored for Solidity into ./libdevcore.   Further cleanup is certainly possible
- The gas price constants in EVMSchedule were orphaned into libevmasm.
- Some other refactorings and cleanups were made to sever unnecessary EVM dependencies in the Solidity unit-tests.
- TravisCI and Appveyor support was added, covering builds and running of the unit-tests (Linux and macOS only for now)
- A bug-fix was made to get the Tests-over-IPC running on macOS.
- There are still reliability issues in the unit-tests, which need immediate attention.    The Travis build has been flipped to run the unit-tests 5 times, to try to flush these out.
- The Emscripten automation which was previously in webthree-umbrella was merged into the TravisCI automation here.
- The development ZIP deployment step has been commented out, but we will want to read that ONLY for release branch.

Further iteration on these changes will definitely be needed, but I feel these have got to sufficient maturity than holding them back further isn't winning us anything.    It is go time :-)

cmake/EthBuildInfo.cmake

@@ -0,0 +1,45 @@
+function(create_build_info NAME)
+
+	# Set build platform; to be written to BuildInfo.h
+	set(ETH_BUILD_OS "${CMAKE_SYSTEM_NAME}")
+
+	if (CMAKE_COMPILER_IS_MINGW)
+		set(ETH_BUILD_COMPILER "mingw")
+	elseif (CMAKE_COMPILER_IS_MSYS)
+		set(ETH_BUILD_COMPILER "msys")
+	elseif (CMAKE_COMPILER_IS_GNUCXX)
+		set(ETH_BUILD_COMPILER "g++")
+	elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+		set(ETH_BUILD_COMPILER "msvc")
+	elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+		set(ETH_BUILD_COMPILER "clang")
+	elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "AppleClang")
+		set(ETH_BUILD_COMPILER "appleclang")
+	else ()
+		set(ETH_BUILD_COMPILER "unknown")
+	endif ()
+
+	set(ETH_BUILD_PLATFORM "${ETH_BUILD_OS}/${ETH_BUILD_COMPILER}")
+
+	#cmake build type may be not speCified when using msvc
+	if (CMAKE_BUILD_TYPE)
+		set(_cmake_build_type ${CMAKE_BUILD_TYPE})
+	else()
+		set(_cmake_build_type "${CMAKE_CFG_INTDIR}")
+	endif()
+
+	# Generate header file containing useful build information
+	add_custom_target(${NAME}_BuildInfo.h ALL
+		WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+		COMMAND ${CMAKE_COMMAND} -DETH_SOURCE_DIR="${PROJECT_SOURCE_DIR}" -DETH_BUILDINFO_IN="${ETH_CMAKE_DIR}/templates/BuildInfo.h.in" -DETH_DST_DIR="${PROJECT_BINARY_DIR}/include/${PROJECT_NAME}" -DETH_CMAKE_DIR="${ETH_CMAKE_DIR}"
+		-DETH_BUILD_TYPE="${_cmake_build_type}"
+		-DETH_BUILD_OS="${ETH_BUILD_OS}"
+		-DETH_BUILD_COMPILER="${ETH_BUILD_COMPILER}"
+		-DETH_BUILD_PLATFORM="${ETH_BUILD_PLATFORM}"
+		-DETH_BUILD_NUMBER="${BUILD_NUMBER}"
+		-DETH_VERSION_SUFFIX="${VERSION_SUFFIX}"
+		-DPROJECT_VERSION="${PROJECT_VERSION}"
+		-P "${ETH_SCRIPTS_DIR}/buildinfo.cmake"
+		)
+	include_directories(BEFORE ${PROJECT_BINARY_DIR})
+endfunction()