Refactoring of lexical_cast: splitting into multiple headers #1
Refactoring of lexical_cast: splitting into multiple headers 2
Corrected spelling of "iteration"
Merge branch 'patch-1' into header_separation

Conflicts:
	include/boost/lexical_cast.hpp
Nothrow nuneric converter moved to a separate file
Lexical converter implementation moved to separate file in the detail folder. minor fixes and improvements
Move all the fixed lexical streamers into a separate file
Move low level float converter into a separate file