Move tests under tests/ directory

This also renames the 'mthemedaemontest' binary to 'stresstest'.
[tests] Import ut_mthemedaemonprotocol from libmeegotouch

Imported from revision fc20afc251f00bb7637da48c57eccb199a842367
ut_mthemedaemonprotocol: include in build again
[tests] Import ut_mcommonpixmaps from libmeegotouch

Imported from revision fc20afc251f00bb7637da48c57eccb199a842367
ut_mcommonpixmaps: include in build again
[tests] Import ut_mimagedirectory from libmeegotouch

Imported from revision fc20afc251f00bb7637da48c57eccb199a842367
ut_mimagedirectory: include in build again