added function pointer struct in order to handle a different service set which operates on an external data source
set point of interface to nodestore. defined ua-service-like operations to interact with generic nodestore
added namespaceManager to handle various datasources
added an example how to register a user defined "readNodes" operation
added missing files
file list - cmakelists.txt (deleted services.c from source file list)
changed operation signature for external data sources
changes within the read service
none
Merge branch 'external_datasource' of https://github.com/acplt/open62541 into external_datasource

Conflicts:
	src/server/ua_services_attribute.c
fixes within the example implementation
Merge remote-tracking branch 'origin/master' into external_datasource

Conflicts:
	examples/opcuaServer.c
	src/server/ua_nodestore.c
	src/server/ua_nodestore.h
	src/server/ua_services_attribute.c
	src/server/ua_services_nodemanagement.c
	src/server/ua_services_view.c
memory leak fixed in service_read
little corrections in interface
removed byteswap.h include from ua_types_encoding_binary.c (not needed and incompatible with MinGW)
moved definition of AttributeID enum to ua_services.h as it may be needed externally
added define for static libs
added ns0 reference hierarchie
Delete CMakeCache.txt
Delete cmake_install.cmake
Delete .project
Delete .cproject
implemented browse service (beta)