Add shebang and PEP 0263 source encoding to main.py
Add shebang and PEP 0263 source encoding to every module

Source encoding should be specified and a shebang helps to execute a module directly (either to start jasper or just for testing purposes).
Remove executable flag from musicmode.py and conversation.py
Add executable flag to client/main.py and boot/test.py
Change python to python2 in start scripts
Add shebang to start.sh
Use executable flag and shebang instead of explicit interpreter in shell scripts.
Remove Shebangs from modules not meant to be executed directly

See https://github.com/jasperproject/jasper-client/pull/154#issuecomment-54882839 for more info.
Merge pull request #154 from Holzhaus/shebangs

Added shebangs and PEP 0263 source encodings