Use docker-java 0.10.3-SNAPSHOT

This version is needed because of bug fixes and improvements in
Bind.parse().

In addition, as DockerClientBuilder now (since 0.10.2) ignores empty
version strings, there is no more need to handle this case here.
Another change is that docker-java now uses ServiceLoader internally to
locate its implementation, which fails with the default classloader.
Bind mount support for StartCommand
Minor refactorings in parser related code

This removes some differences in the two parsers.
Rename "Test syntax" to "Check syntax", remove progress message

For such a short-runing method, a progress message just appears as a
short flickering.
All help files for StartCommand are considered again

Prior to this change only help files for entries before the line
changing the descriptor variable were considered.

Also updated some messages to adapt a common style