usrp2: try/catch for first send of discovery routine

This send can fail with a network down/unreachable error.
The try/catch allows for discovery to continue.
Merge branch 'maint'
b200: added more formal product ids
b200: lower clock rate is 5MHz due to DCM
Corrected PDD1 config on gps_nmea neet
uhd: benchmark use builtin samp calculation
uhd: added UHD_HEX helpful print macro
utils: usrp_n2xx_net_burner_gui no longer ignores dont-check-rev option
Merge branch 'maint'
uhd: fix get_xx_freq_range to use analog bw/2

The proper equation should be:

max_freq = max_lo + min(adc/2, bw/2) - sr/2
Merge branch 'maint'
uhd: added multi-thread build flag for msvc
usrp2: fix firmware rx clear register offset

When an ICMP dest unreachable pkt arrives,
the fw needs to know how to shutoff the DSP.
This offset for the reset register was
broken by a previous fix for register overlap.
Merge branch 'maint'
examples: changed examples that force usage of all channels to allow user to input which channels to use
test_timed_commands: explicitly set RX stream time to be less than recv timeout
usrp2: sc8 format swap for vita compliance
convert: sc8 swap for vita compliance
convert: added sc12 and fc32 converters
Merge branch 'fpga_master' into master_converter_work