Jack's fix for sync period constant value.
Added a "hard" reset line to QDR config.

This reset holds QDR reset high until it is de-asserted again by the OPB.
A normal "soft" reset can still be done by writing a 1 to offset 0 but if a
"hard" reset is needed this can be done by writing 256 to offset 0 instead.
Just be sure to write a 0 after that.
Merge branch 'master' of https://github.com/casper-astro/mlib_devel
[QDR] Added "&& !cal_fail" to the PHY output mux.

Now if bit alignment fails instead of connecting the outputs (addr, read/write
enable, write data, etc) to the burst alignment logic which will not be started,
the PHY instead defaults to connecting the user logic to the QDR.

This has the benefit of being able to still read/write from the QDR's even
though calibration fails (which it has been for various frequencies).
Changing the default clock on R1 to sys_clk

The default clock used to be dac1_clk for some stange reason.
It is now set to sys_clk.
Merge branch 'master' of https://github.com/casper-astro/mlib_devel
Merge remote-tracking branch 'ska-sa/master' into crowley
Added an option to use 100 MHz REFCLK for IDELAYCTRL in roach_infrastructure.v.

By default roach_infrastructure will use the 200 MHz sys_clk-derived clock for REFCLK
as it normally would however when the environment variable IDCTRL_100 is set the core
will use 100 MHz instead. This is of course a non-Xilinx-approved clock rate but may
nevertheless solve QDR calibration failures at fabrics rates lower than 200 MHz. It
definitely works for 143 MHz (the SMA wideband correlator phase-I rate).

USE this feature AT YOUR OWN RISK.