libbladeRF: Removed end_fpga_programming() call from FPGA load

This function was causing intermittent failures because it would
return an error if it detected that that FPGA was not yet loaded,
which is a likely possibility.

Since this function no longer issues a vendor request to device to
perform a post FPGA load operation, it serves no purpose and has been
removed.
libbladeRF: add initial XB-200 transverter support
bladeRF-cli: add initial support for XB-200
hdl: add XB-200 support

This commit introduce XB-200 support in HDL. XB support introduces a new
direction configurable GPIO bank that is used to control peripherals on the XB
port. The xb_mode for the XB-200 board overrides exp_goio so it is used as
a chipselect pin for the ADF4351.
hdl: swap XB SPI pins

To match the design of the XB-200 these pins will now be changed. This change is
backward compatible.
hdl: fixup pin assignment for exp_spi_clock
hdl: bump FPGA version to 0.0.5
libbladeRF: Removed incorrect usage of error_conv()

In this case, status is already a libbladeRF error value.

Fixes #257
bladeRF-cli: Added "pretty print" of LMS reg readback to poke command
libbladeRF: Fixed Windows build issue (warning + /WX)

Removed narrowing assignment from double to unsigned int.
WIP: Modify the RXVGA2 calibration routines.
Calibration update.
libbladeRF: Moved LPF DC tuning value write into address loop

This is just for readability. There's no functional change, since
there's only 1 address to loop over anyway.
libbladeRF: Added register settings from LMS FAQ to DC calibration fns

The following changes have been added to lms_dc_cal_loop() and
lms_calibrate_dc(), based upon recommendations from the LMS 6002D FAQ
(version 1.0r10).

    - Use the DC_REGVAL to determine success or failure, as DC_LOCK
      is reported (in the FAQ) to be unreliable. Retry if the result is
      31, setting the count to DC_CNTVAL to 0.

    - Enable DC comparators during DC calibration (default), and
      disable them upon completion to address linearity issues.

    - Disable DACs while performing TXLPF DC calibration
bladeRF-cli: [WIP] First cut at RX DC auto calibration

Includes a workaround for convergence issues - further investigation
required. General cleanup and documentation changes still required.
bladeRF-cli: [WIP] Use fewer buffers for dc cal, start with cal at 0,0
bladeRF-cli: [WIP] Added TX DC cal operation. Further cleanup required.
bladeRF-cli: Check for divide-by-zero in interpolation function
libbladeRF: Be explicit with RXVGA2 cal.

It was seen that the VCM will sometimes come back in a bad state.
This register has a very well known value that it should be.  Setting
it to be these explicit values seems to help alleviate putting the
LMS is a bad state.

Investigation is required to figure out why the VCM is coming back
scrogged.
bladeRF-cli: Extend out DC, GAIN and PHASE max/min.