This is very useful on setting/getting registers in
modules that have multiple channels with the same
register definitions.

This way avoids users needing to know how this
is implemented internally and, obviously, decreases
the chances of error.

We don't need to destroy zactor PIPE sockets,
as CZMQ zactor infrastructure already does this.

RFREQ is a 38-bit number, with the 10 MSB
the integer part and the 28 LSB the fractional
part. So, we need to divide RFEQ by 2^28 prior
to the calculation.

This was causing a segfault when reading the frequency

As libbpmclient changed, we need to update it there too.

In this way, we can standardize how the
functions are called and handled.

This fixes #115 github issue

Note that this requires at least
lnls-dig/bpm-gw@27a4af84b1

This is necessary as lnls-dig/bpm-gw@6a78088ab1
and lnls-dig/bpm-gw@950b4b2d18

This causes an assertion error as the zactor
infrastructure needs the PIPE after the thread exits.

This fixes #116 github issue.