Add experimental Lua support to Ettercap

- Enabled via ENABLE_LUA=On
- Depends upon LuaJIT
- Will use bundled LuaJIT if system doesn't provide.
- Leveraged via --lua-script command line.
- Currently, Lua scripts can hook to any hook point. Will eventually
  move toward drop-in replacements for C-based protocol dissectors.
Bundle Curl with Ettercap
Updated INSTALL to mention bundled curl
Fixed end of stack bit checking.
Merge pull request #172 from jacob-baines/mpls_depth

Fixed MPLS End of Stack Bit Checking
Merge pull request #158 from justfalter/bundle_curl

Bundle Curl with Ettercap
Added mDNS spoof plugin
Initial import  of lua basics, more to come
fixing omitted files
Adding in string additions
final mods to scripts to bring them up to speed
Fixed remote browser plugin
Added SRV query handling to DNS spoof
Sync ettercap_ffi w/ recent ec_packet.h change
Merge branch 'add_experimental_lua_support' into lua_staging
Added packet metamethods.
Added third-party lua stdlib library.
Changed --lua-script FILENAME load behavior

- First, it checks to see if it can load FILENAME directly. This can be
  a relative path from the current working directory, or a full path to
  a file.

- If that fails, then it will 'share/lua/scripts/' install directory for
  FILENAME. You are now expected to provide the file extension
  (previously, it would auto-append '.lua')
Better error handling for lua script loading

- Fatal error if the lua script doesn't parse properly.

- Script load errors now exit using ettercap standard methods
Added more flag handling, stopped set_data overflow