Settings cleanup

Add a setting that, if enabled, cause all of the pages mapped by the
address space to be memory-resident until the setting is disabled.

Also rename setTestModeEnabled() to enableTestMode().
Move DBus service and path information to a separate header

Make this information referencable from other files.

Issue:  #8
Session object implementation

Only the most important properties and methods are implemented at the
moment.

Issue #8