The original FindMember() may access out-of-bound of the 'const char*
name' parameter.
This commit firstly follows
f86af8c232
However, this must incur an StrLen() for name. A better API is by using
Value as the name, which provides the length of string internally. So a
set of new API are added:
operator[](const GenericValue& name)
FindMember(const GenericValue& name)
RemoveMember(const GenericValue& name)
During refactoring, it also adds an API:
RemoveMember(MemberIterator m)
which can be used for other purpose, such as removing a member while
iterating an object.
Fixes#7