From Julian Book: Better marker size.
.O implemented.
.O command.
Merge branch 'master' of https://root.cern.ch/git/root
Doc for ForceUpdate option in TDataSetManagerAliEn
PROOF sched returns all workers in dynamic mode
WIP on the PROOF remote player for dynamic workers

Started working on the TProofRemotePlayer to allow the Process() method
to set to "process" status some new workers while already processing.
This is to pave the way for the dynamic workers addition.
Some debug messages added in TProofServ
TProof method to activate workers dynamically

The GoMoreParallel() function, unlike the GoParallel() function, is
capable of activating new workers while an analysis is progressing.
This is currently a WIP.
Removed stale debug message
Fixed some PROOF debug messages
PROOF: dynamic/include path on a subset of wrks

AddDynamicPath() and AddIncludePath() functions accepted a list of
workers: the Broadcast() was correctly sent to the subset, but the
Collect() was performed on all active workers. This is not OK when
adding workers dynamically since we want to stop the packets events
until the new workers are initialized, and a broad Collect() resumes
packets processing.
PROOF: Upload/EnablePackage on a list of wrks

UploadPackage() and EnablePackage() now take a list of workers as
argument. Useful for dynamic workers, to avoid reuploading and
recompiling everything on the existing workers.
Current selector sent to dynamic workers in PROOF
No Collect() needed when adding dynamic PROOF wrks
TPacketizerUnit deals smoothly with unknown wkrs

Primarily for debug purposes: when a GetNextPacket() is triggered by a
worker unknown to the packetizer, does not make a fatal assertion any
more, but prints a warning message to the master's console.
Sending a dyn wrks message using async interface
Don't notify for max workers in PROOF dyn mode

This is done to avoid flooding client's console.
PROOF: poll for new dyn wrks every once in a while

Timestamp check to avoid contiuously polling for new workers before
each call to TMonitor::Select().
PROOF dyn workers: more appropriate variable name
Separate PROOF Player function for adding workers