Add support for FreeSRP

This patch adds support for both receiving and transmitting using
the FreeSRP. More information on the FreeSRP can be found at:

http://freesrp.org

The gr-osmosdr blocks added make use of libfreesrp, the library
required for interfacing with this device. The libfreesrp source
code is freely available at

https://github.com/freesrp/libfreesrp

Usage example:

osmocom_fft -a "freesrp"

1 files changed, 1 insertions, 0 deletions

diff --git a/AUTHORS b/AUTHORS
index b654b84..2fd882c 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -6,3 +6,4 @@ Josh Blum
 SDRplay Ltd.
 Pavel Demin
 Marcus Müller
+Lukas Lao Beyer