Qt: Add encryption test and refactor testsuite
* lang/qt/tests/Makefile.am: Add t-encrypt and t-support. * lang/qt/tests/t-support.cpp, lang/qt/tests/t-support.c (QGpgMETest): New. Class to handle common cleanup / init. * lang/qt/tests/t-keylist.cpp, lang/qt/tests/t-keylocate.cpp, lang/qt/tests/t-ownertrust.cpp, lang/qt/tests/t-tofuinfo.cpp: Inherit QGpgMETest. * lang/qt/tests/t-encrypt.cpp: New. Test Symetric and Asymectric encryption. Mixed encryption test is disabled.