Using static for LUTs

[bryates]

This is an alternative to #351 to address an issue where CMSSW wastes CPU cycles for emptyUnit and nearFull3Unit. All luts are now declared as static, so this should fix the issue.

[bryates]

This seems to improve timing as well (unless I'm behind on the latest numbers)

#=== Post-Implementation Resource usage ===
CLB:            580
LUT:           2250
FF:            2827
DSP:              2
BRAM:             2
SRL:             13
URAM:             0
#=== Final timing ===
CP required:    4.000
CP achieved post-synthesis:    3.227
CP achieved post-implementation:    3.202