In Interest, change default MustBeFresh to false
Previously, if an Interest had MustBeFresh true, then NFD would match a Data packet with no freshness period. On May 23, a commit to NDN-CXX changed this so that a Data packet with no freshness period does not match an Interest with MustBeFresh true.
Since this breaks some integration tests and applications (which don't receive the requested Data packet if it doesn't set a freshness period), we should change the Interest constructor so that the default value of MustBeFresh is false. This should not cause problems since most applications which rely on Data packet freshness already set MustBeFresh true for their Interests. (For example, ChronoSync, PSync and NDN-RTC.) And changing the MustBeFresh default to false will make it more likely for an application to receive the requested Data packet, so this should not cause a problem with developers working with the library for the first time. Also, this should not cause a problem with developers familiar with NDN-CXX, since it already sets MustBeFresh false by default.
If no one objects, we will make this change in one week, on Monday, November 25.