Naming refactoring.
Documentation fix.
Fixed bug with always positive exit codes.

Due to asynchronous nature of action invocation, exceptions haven't properly propagated inside event loop to the root cocaine-tool trigger, which led to the incorrect exit code assigning. Fixed with moving `catch` blocks inside asynchronous action handler, so they are actually catches errors inside event loop.
Merge branch 'fix-ExitCodes' into develop

Conflicts:
	cocaine/tools/cli.py
	scripts/cocaine-tool
Merge branch 'feature-Refactoring' into develop
Oops, broken after merge.

 * fixed broken import statement.