cgc_list: add new functions
cgc_list: fix several functions

fixed functions:
- erase
- push_back
- insert
cgc_list: refact
cgc_list: add clean function
cgc_list: minor edits
Merge branch 'dev' into list
cgc_list: improve documentation
Merge branch 'list' into dev
bump v0.3.0
change implementation and interface

- list and vector creation now require:
  - element size information
  - a copy utility
  - a clean utility
- lists do not require a free and an alloc utility
compile tests separately
bump v0.4.0
doxygen: fix CALLER_GRAPH option
cgc_list: update and fix doc
cgc_vector: update doc, fix error handling
types: fix doc
const
cgc_list: update doc
cgc_string_vector: temporary doc warning fix
cgc_list: fix shadowing declaration