first version of partio4Houdini

a collection of partio 4 houdini tools:
SOP_partio: a read/write node
ROP_partio: a write ROP
partioConvertCmd: a command for converion of the fly by the internal
houdini nodes
adding basic node compile makefile

this will be removed when cmake configured
Merge remote-tracking branch 'milo-green/master' into partio4Houdini

adding milo green's   partio4Houdini contrib
Update ROP_partio.C

updating for H12.5
Update partio_houdini.C

updated for H12.5
Merge branch 'redpawfx' into partio4Houdini
working on getting milesGreen's   Partio4Houdini  contrib  compiling in the tree  with  cmake, not quite there yet... the plugin compiles, but does not show up in houdini...  but his   makefile version of the compile will... I'm a newb at HDK...
Merge branch 'milo-green/master'

Conflicts:
	contrib/partio4Houdini/src/ROP_partio.C
	contrib/partio4Houdini/src/partio_houdini.C
cmake compiles  the houdini plugin now.  took a little hacking... and  there's still one spot where  include path is  hardcoded.. feel free to clean  this up a bit further.
ran the code thru the standard formatting  grinder  to conform it to the rest of the project
formatting/ license updates and some help strings tweaked. added in proper build outputs for the houdini plugin and icons
fixes issue #27
added a  partio attr on the particle shape itself  that defines  which entries have been checkboxed,  it works "live"  so as many changes that are made happen on each check/uncheck.
Also added  better directory handling  and defaults for  unknown directory stuff.
added support for changing the directory path manually  by editing the text field.
fixing  issue #24
added support for  "byFrame"  attribute  to  skipframe playback  particle caches
setting  disney  partio for houdini  stuff to not build.
Merge branch 'redpawfx' into partio4Maya
forking  this problem to work on possible solutions.
fixed  the mem leaks in the partviewer, reset function seems to actually work correctly...  I missed another leak that I was not accounting for.
Merge branch 'frameMemLeak' into partio4Maya
this adds the  partio base code for  a "Reset" command  to  the partio lib
which hopefully will be able to  fix the mem leak in the maya plugins now  as well
fixed  partio4Maya  visualizer and  instancer  memory leak,  would still like to  implement this better in the  partio core.
Merge branch 'partio4Maya'  into redpawfx