Fix declaration of ws_statement_append_indirect
Add more extensive docu to ws_command
Extend documentation of ws_argument
Extend documentation of ws_statement
Add documentation to macros in list.h
Extend documentation of ws_command_list and ws_command_cnt
Rename getter in bool.{c, h}
Rename getter in string.{c, h}
Correct getter calls in union.c and utils.c
Correct getters in bool.c and logical.c
Merge pull request #308 from xVin/standardize-getters

Standardize getters
Merge pull request #300 from neithernut/add-commands-extensive_docu

Add commands extensive docu