Initial import of filter parser

Current runs as its own program, partially implemented.
Commiting for the sake of sharing access / backup.
Still needs a lot of work.
Move filter files into src/

- Makefile still needs work, is not compiling
Mildly working build process with argument parsing
Add support for holding an index instead of fieldname
Incredibly hacky evaluate implementation
Drop packets that don't pass the filter in recv
Build filter using CMake
Update build to -Werror, #pragma to ignore in lexer.l
Working filtering, still needs cleanup and optimization
Remove debug printf calls
Move stack.h and stack.c to lib
Untested iterative implementation of evaluate
Switch to the iterative evaluator
Revert "Switch to the iterative evaluator"

This reverts commit eeb5ddcf0cffd78762b7b223354736f076b21e05.
Revert "Untested iterative implementation of evaluate"

This reverts commit f2ba9d76215f2bb22fde0f71850cdd541ee59eeb.
Fix casing error in #include
Improved filter validator

- Can no longer do "stringfield = INTEGER" or "intfield = string"
- Print slightly more sane error messages
Fix minor styling errors
Merge in changes to allow filtering received packets

Merge branch 'output-filter'

Conflicts:
	src/zmap.c
Fix compile warnings in blacklist.c