Add string.c to CMakeList.txt
Add basic ws_value_string implementation
Add method stubs to string.c

Conflicts:
	src/values/string.c

Conflicts:
	src/values/string.c
Add implementation of ws_value_string_init()
Add implementation for ws_value_string_new()
Add implementation for ws_value_string_get_str()
Add implementation for ws_value_string_set_str()
Add implementation for value_string_deinit()
Merge pull request #168 from xVin/add-string_value_type

Add string value type
Added id to monitor
Merge pull request #193 from TheNeikos/add-id_to_monitor

Added id to monitor
Added ws_object_attribute type
Added example object attribute table
Add ws_object_attr() for getting attrs inclusive stub
Add implementation for ws_object_attr_read()
Add function for getting the type of an attribute (and stub)
Add implementation of ws_object_attr_type()
Add ws_object_get_value_for_attr() method
Add stub for ws_object_get_value_for_attr()
Outsource attr-type-value-type map into static const