Parses the version out of libjsonnet.h

def get_version():
    """
    Parses the version out of libjsonnet.h
    """
    with open(os.path.join(DIR, 'include/libjsonnet.h')) as f:
        for line in f:
            if '#define' in line and 'LIB_JSONNET_VERSION' in line:
                v_code = line.partition('LIB_JSONNET_VERSION')[2].strip('\n "')
                if v_code[0] == "v":
                    v_code = v_code[1:]
                return v_code