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 :-)

test/libsolidity/SolidityExecutionFramework.h

@@ -22,25 +22,33 @@
 
 #pragma once
 
-#include <string>
-#include <tuple>
-#include <fstream>
+#include <functional>
+
 #include "../TestHelper.h"
 #include "../RPCSession.h"
-#include <libethcore/ABI.h>
-#include <libethcore/SealEngine.h>
-#include <libethereum/State.h>
-#include <libethereum/Executive.h>
-#include <libethereum/ChainParams.h>
+
+#include <libdevcore/ABI.h>
+#include <libdevcore/FixedHash.h>
+#include <libevmasm/Instruction.h>
+
 #include <libsolidity/interface/CompilerStack.h>
 #include <libsolidity/interface/Exceptions.h>
-#include <libethcore/BasicAuthority.h>
-#include <libethcore/SealEngine.h>
 
 namespace dev
 {
 namespace solidity
 {
+	/// An Ethereum address: 20 bytes.
+	/// @NOTE This is not endian-specific; it's just a bunch of bytes.
+	using Address = h160;
+
+	// The various denominations; here for ease of use where needed within code.
+	static const u256 ether = exp10<18>();
+	static const u256 finney = exp10<15>();
+	static const u256 szabo = exp10<12>();
+	static const u256 shannon = exp10<9>();
+	static const u256 wei = exp10<0>();
+
 namespace test
 {
 
@@ -275,8 +283,7 @@ protected:
 	dev::solidity::CompilerStack m_compiler;
 	Address m_sender;
 	Address m_contractAddress;
-	eth::EnvInfo m_envInfo;
-	u256 const m_gasPrice = 100 * eth::szabo;
+	u256 const m_gasPrice = 100 * szabo;
 	u256 const m_gas = 100000000;
 	bytes m_output;
 	std::vector<LogEntry> m_logs;