Ensure model derivation occurs before model dependent processing (sky…

…nav#180).

[ttpe] fix artifact description

Fix checkstyle and findbugs warnings.

[ttv] fix checkstyle and findbugs warnings

[*] fix findbugs warnings

[*] eliminate symlinks

[*] fix checkstyle and findbugs warnings

[ttv,ttx,ttpe] support conditional styles in ISD; initial support for…

… forced display mode

[ttv] add prohibited writing mode unit tests

[ttv] further reorganize tests by model