remove some TODOs.
Fixed typos.
wrote class name
wrote token
wrote safely-derived pointers.
Fixed a typo.
wrote allocation function
wrote deallocation function
Merge pull request #111 from hiroshi-manabe/typo-nobe

Fixed typos.
Merge pull request #112 from hiroshi-manabe/typo-toshite

Fixed a typo.
wrote constant expression
Merge branch 'gh-pages' of https://github.com/EzoeRyou/cpp-book into gh-pages
resolve all TODOs save for Copying and moving class objects
monor wording change.
fix typo.
Merge pull request #113 from yohe/fix

fix typo.
fix typo
Merge pull request #114 from k-takata/fix-typo6

fix typo
explain that the variable declared in the condition of the while statemet will be destoryed and constructed each time the condition is evaluated.