Merge branch 'debris_sven_build' into build_enhancement
provided my own FindJsonRCP.cmake
WIP: Cryptopp and json-rpc-cpp correctly downloading and compiling on
Linux. Main cpp-ethereum buildfile finds dependencies, but does not
compile yet
compiles fine now (on Linux) with both cryptopp and json-rpc-cpp dependencies
Merge branch 'build_enh' into sven_build

Conflicts:
	extdep/CMakeLists.txt