test-spice: add watch option

[yrtimiD]

adds -w / --watch option to the test-spice tool allowing faster checking of applet changes
if watch is requested, next will happen:

1. applet is validated and installed (as in default mode)
2. applet uuid folder is monitored with inotifywait tool (standard inotify-tools package must be installed)
3. on each file change under uuid folder validate, copy and reload are performed (no more than once in a 1 sec)

[yrtimiD]

I'm not very familiar with python, will appreciate any corrections