Update fft_core and modify latencies

The fft_core is updated to mlib_devel version 2779284.  The latencies have been
changed:

Latency | Old | New
Add     |  4  |  2
Mult    |  3  |  3
BRAM    |  2  |  4
Convert |  5  |  3
Input   |  -  |  1
Between |  -  |  2

The old FFT block did not have "Input Latency" nor "Latency between biplexes
and fftdirect".  Add Latency changed to 2 because "Use DSP48 in adders" is now
selected (it was not selected before).
Update fft_core netlist

Built using mlib_devel version 2779284.
The new FFT library block has a UFix32_0 oflow(!)

Instead of a single bit oflow signal, the new fft_wideband_real library block
outputs a UFix32_0 oflow signal.  That seems excessive to say the least, but
that's how it is (for now at least) so we have to deal with it.
Change fft_core to wrap rather than saturate

Also update it to mlib_devel d5fd7cd.
Update fft_core netlist

Built using mlib_devel version d5fd7cd.
Update sma_corr to mlib_devel version d5fd7cd

Ran update_casper_blocks('sma_corr').
Updated sma_corr.mdl to mlib_devel a125547

Ran update_casper_blocks('sma_corr') to update all CASPER blocks with new
ones from mlib_devel commit a125547.
Ran resynth_netlist on fft_core netlist
Modify .gitignore to track bof files
Add sma_corr_2013_Aug_25_1657.bof