change conceptEntry to entry

The TBX steering committee asked that we rename the conceptEntry
element to just "entry", which is accomplished in this commit. The
change affects the schemas, the name of the accessor method, and
also the comments referring to the element.
don't use use_ok

Replace `use_ok` statements with regular ol' `use`. `use_ok` is almlost
never the right thing to use- it doesn't die if the use fails.
Trust BUILD subroutine via TrustPod
New CPAN release of TBX-Min - v0.04

    "conceptEntry" element changed to "entry"