make search_kind() more useful with a predicate
add missing cursor kind for function declaration
add functions to check cursor kinds by CXCursorKind
add C++ and Vim API to deduct function return types
improve visitor name to deduct type
implement return type deduction for functions
Fix auto type detection from the type name
deduct type of a function or variable declaration
add C++ and Vim API to deduct type of function or variable declaration
Merge branch 'deduct_func_return_type'

Conflicts:
	lib/libclang-vim/helpers.hpp
update title, have done variable and function declaration deduction