Merge tag 'v0.3.1' into develop

see changelog.md
loosening too strict request checking.
prepared jsonrpc legacy support in architecture
added basic support for jsonrpc1
added hybrid jsonrpc v1 and v2 handler
basic v1 server-testcases
bugfix for hybrid server version
refactored hybrid server and improved test coverage
added jsonrpc v1 client capability, yet without test.
bugfixes for rpc v1 client and testcases
refactorings, bugfixes and additional testcases for client -> 100% line
coverage
hiding rpcprotocolclient from API
adapted installed header (minimalized api)
set new SOVERSION
Merge branch 'feature/jsonrpc1' into develop
bugfix to adapt to new interface
bugfix in unit test
prepared release, updated documentation
Merge branch 'release/v0.3.2'

Conflicts:
	README.md