It's like a label but with fixed dimensions and maximum
characters' capacity at creation time.

This function is used to print rates (say '1kb/s' or '16Mb/s').

[-1 29] was not very pleasant for MCS 28 or no DCI (value is -1 in this case).
[-2 30] looks better.

The problem was visible when DL MCS was set to 20
(do a ping -c 192.172.0.1 -i0.2 to get it). The dots
were not plotted at the exact line of the tick mark.

Not sure the fix is always correct.

No big deal anyway.

Helps visualize MCS usage over time.

A new logger is there: the "ticked TTI logger".
Similar to TTI logger (used by the PUCCH1 energy plot)
but takes another input, the "tick" (think subframe)
and a default value for when no event is triggered between
two ticks.

This is used for the UL and DL MCS plots in enb.c (next commit).

- add mcs to ENB_PHY_DLSCH_UE_DCI
- add mcs, round, first_rb, nb_rb, TBS to ENB_PHY_ULSCH_UE_DCI

tested with both EXMIMO and USRP. performance better than in master branch.

When the user clicks on "next UE" or "prev UE" we change the
filters of loggers.

At the same time, the main thread of enb.c processes events
received from the soft-modem and uses the filters, some of them
maybe in the process of being changed.

Changing the filters is not atomic and has to be protected.

Just below the logo you see the current UE, eg. [UE 0],
and near that you have two "buttons" [prev UE] and [next UE].

You click with left button of mouse on those and the various
plots that depend on the UE are now done for the new UE (say UE 1
instead of UE 0 if you click on [next UE]).

The plots are not cleared when you switch.
Let's say it's a feature.

Conflicts:
	targets/PROJECTS/GENERIC-LTE-EPC/CONF/enb.band38.tm1.exmimo2.conf

Something went wrong somewhere in the commit history, the function
was not correct.

The most obvious symptom was that way too much SR (scheduling requests)
were given to the UE whenever it had some PUCCH to send.

The case for TDD has not been tested.

add ndi to trace ENB_MAC_UE_DL_SDU