Build Rhubarb as shared library

[JuliusNmn]

Is anyone else interested in using rhubarb as a shared library? i'm no cmake expert, but i hacked around in rhubarb/CMakeLists.txt and got it to build a shared library.

# ... rhubarb-lib
add_library(rhubarb-lib
	src/lib/rhubarbLib.cpp
	src/lib/rhubarbLib.h
)

to

# ... rhubarb-lib
add_library(rhubarb-lib SHARED
	src/lib/rhubarbLib.cpp
	src/lib/rhubarbLib.h
)

i had to modify my header search paths and actually got it to run, but it's hacky. i would prefer it to build a shared library and provide an include dir.