Preliminary membrane version

Not too representative yet - preparing for membranes functionality tests
Improvements  to membrane test scene
significant progress in membrane code development

but still not complete
minor changes
minor changes
some more progress in membrane code development
some more progress
some more progress
added some vector math for membranes processing
Membranes are finally implemented and looks working correctly

Actual version performs correction of positions (coordinates) of
particles involved into interaction with membranes. Velocities also need
corrections, but this is not done yet.
Video is here: https://www.youtube.com/watch?v=xWOPCOxHG70
More correct membranes behavior + worm body shell demo
Worm body generator (elastic shell + outer membranes + muscles + inner liquid) demo

Uncomment line 73 in owPhysicsFluidSimulator.cpp  to switch off
physics-induced movement of the scene.
Important changes done

1) Improved worm body generation
2) Problem of pairs of particles with coincident coordinates - solved
3) Problem of keeping 1:1 aspect ratio at any window width and length
values - solved
small changes

1) minor bug in graphics fixed
2) worm initial position changed (rotated 90 degrees)
minor changes
First 24 muscles (dorsal right muscle bundle) implemented

muscle cells are enumerated according to the schema
(http://www.wormatlas.org/hermaphrodite/musclesomatic/Images/musfig15leg.htm)
muscles which are active (signal > 0) are displayed with thicker lines.
First five muscles can be activated with keyboard keys from '1' to '5'
2 full muscle quadrants (DR and DL) are working

DR01..DR24 indexes are 1..24 according to
http://www.wormatlas.org/hermaphrodite/musclesomatic/Images/MusFIG15.jpg
DL01..DL24 indexes are 25..48, (same numbers as on the image, but
increased by 24)
Full set of 24*4 body muscles implemented

Muscle cells enumeration according to
http://www.wormatlas.org/hermaphrodite/musclesomatic/Images/musfig15leg.htm
starting from DR quadrant. Enjoy!
Note: in real worm VL quadrant contains only 23 muscles (not 24).  In
simulation there are 24 muscle cells in this quadrant for symmetry.
They are completely symmetrical to those in VR quadrant, so send signals
for 22 and 23 real muscles to 23 and 24 muscles in simulation,
correspondingly (and nothing to 22-th muscle of simulation) for VL
quadrant.
Contact me if you have any questions.
test scene for c. elegans swimming test
minor improvements of muscles mapping