add igraph cmake glue

refs #27
rename node to host

refs #27
initial files for new topology

refs #27
graphml config/input

+ added config and parser to handle a new topology element
  that will be used to enter the path to the graphml file
+ initialized topology with that path using igraph, and
  added some basic sanity checks

refs #27
iterate graph vertices and edges and check attributes

refs #27
stubs for new address manager

refs #39
fix ID/index, get default 'id' attribute

refs #27
refactor, stubbed out edge weights and shortest path

refs #27
Merge branch 'master' into next

Conflicts:
	src/host/shd-host.c
fix previous merge and build errors
replaced old shadow topology with new igraph topology

-replaced all uses with new topology functions
-added new dns system to handle name/ip resolutions

this compiles, but has not been tested. and its not yet complete:
there are currently graph attribute errors and the topology
connect/disconnect functions are not yet implemented.

refs #27
handle newer igraph version

refs #27
workaround for igraph's broken graph attributes

igraph ignores graph attributes for some reason. so we attach
graph metadata into a dummynode vertex and extract it from there.

refs #27
worked out kinks after switching to igraph topology

fixed some ID!=IP errors that happened when allowing requested
ip addresses.

still have to clean up topology and actually attach hosts to poi
topology nodes based on cluster and longest ip prefix.

refs #27
Merge branch 'master' into next
stubbed out new minimal torctl plugin

compiles but not tested.

refs #172
refactor path and cluster, rw locks, virtualIP map for poi assignment

refs #27
connect addresses to topology pois based on geocode hint

also some minor bugfixes to pass a functional test

refs #27
add shortest path timer

so we can track overhead associated with computing shortest paths

refs #27
fix routing, update scallion minimal example, convert topology to graphml

+ changed the default scallion xml name from hosts.xml to shadow.config.xml
+ shadow.config.xml should now be wrapped in <shadow></shadow> root tags
+ built-in examples are now broken because igraph needs a file

refs #27