(T0 pulse is generated when run_active goes high.)

Partially catching up ( manually ) with Paolo's code .

* Edited build_tlu_firmware.sh - no need to execute script to change top level entity

* enclustra_ax3_pm3_a35.dep - Don't include IPBus top level dep file. This allows the top level entity to be in local directory

* Edited T0_Shutter_Iface_rtl.vhd to enable shutter when T0 is pulsed. Modified TLU_v1e.py and startTLU_v1e.py accordingly
( N.B. **** There is a bug in the code that enables/disables shutter when pulseT0 is written. )

* Added ipbus_syncreg_v and dependencies to projects/TLU_v1e/firmware/cfg/tlu_1e.dep

* Edited top level ( top_enclustra_tlu_v1e.vhd ) to add extra shutter_veto port in T0_Shutter_Iface_rtl

* Moved counterWithResetPreload_rtl.vhd to counterWithResetPreset_rtl.vhd
* Changed dep file to include new files.
* Minor change to dualSERDES_1to4_rtl.vhd to hopefully remove a warning message

* Adding SyncGeneratorIPBus_rtl.vhd , which is a wrapper to SyncGenerator_rtl.vhd , giving an IPBus interface
* Modifications to SyncGenerator_rtl.vhd to tidy up code

* Created SyncGenerator_rtl.vhd , which generates trigger veto and shutter signals. (needs to be wrapped in IPBus interface)
* Created counter with preload to top bit as well as reset

It is necessary to set up Vivado and Cactus environment before
running the script.

Added files to generate sync/spill signal based on a trigger input. Still having problems with timing convergence

Moved all existing HDL files to "legacy" subdirectory. Created directories in ipbb "standard" layout