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/FindJsoncpp.cmake

@@ -0,0 +1,50 @@
+# Find jsoncpp
+#
+# Find the jsoncpp includes and library
+# 
+# if you nee to add a custom library search path, do it via via CMAKE_PREFIX_PATH 
+# 
+# This module defines
+#  JSONCPP_INCLUDE_DIRS, where to find header, etc.
+#  JSONCPP_LIBRARIES, the libraries needed to use jsoncpp.
+#  JSONCPP_FOUND, If false, do not try to use jsoncpp.
+
+# only look in default directories
+find_path(
+	JSONCPP_INCLUDE_DIR 
+	NAMES json/json.h
+	PATH_SUFFIXES jsoncpp
+	DOC "jsoncpp include dir"
+)
+
+find_library(
+	JSONCPP_LIBRARY
+	NAMES jsoncpp
+	DOC "jsoncpp library"
+)
+
+set(JSONCPP_INCLUDE_DIRS ${JSONCPP_INCLUDE_DIR})
+set(JSONCPP_LIBRARIES ${JSONCPP_LIBRARY})
+
+# debug library on windows
+# same naming convention as in qt (appending debug library with d)
+# boost is using the same "hack" as us with "optimized" and "debug"
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+
+	find_library(
+		JSONCPP_LIBRARY_DEBUG
+		NAMES jsoncppd
+		DOC "jsoncpp debug library"
+	)
+	
+	set(JSONCPP_LIBRARIES optimized ${JSONCPP_LIBRARIES} debug ${JSONCPP_LIBRARY_DEBUG})
+
+endif()
+
+# handle the QUIETLY and REQUIRED arguments and set JSONCPP_FOUND to TRUE
+# if all listed variables are TRUE, hide their existence from configuration view
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(jsoncpp DEFAULT_MSG
+	JSONCPP_LIBRARY JSONCPP_INCLUDE_DIR)
+mark_as_advanced (JSONCPP_INCLUDE_DIR JSONCPP_LIBRARY)
+