p4_dscm. Fix issues with sync.

Only sync if there are files to sync.
Add prints to show which CL is being synced, and the type of sync.
Fixes to full sync, so it syncs to the most updated CL required for the
full sync.
p4_dscm. Start implementation of change command.

Add change command.
Add submit command - skeleton only.
Start implementation of change command - validate the remote repository
and branch.
p4_dscm. Add support for verbose option.

Verbose option prints all SCM commands and their output.
p4_dscm. Bug fixes to path calculations.