Merge pull request #1 from sidorovis/master

merge
2_4 done
solved 2_5
Solution 1.5 added
Modified for solution 1.5
Remove logging
Modification to support older compilers
Added 2_6
fixed 2_6
fixed error
adding puzzles.doc for 5 week
Merge pull request #127 from nick0lay/master

Task 1.5 from nick0lay
Merge pull request #141 from vvysokikh/master

solved 2nd task by vvysokikh
Merge branch 'master' of github.com:sidorovis/cpp_craft_1013
fix vector_tests
Merge branch 'master' of https://github.com/alstrokov/cpp_craft_1013