Viewer: fix Binary Matlab viewer info to use '#' instead of '%'

The % character for comments in info files was removed in

  7c43ebc8e6c "only use # for comments in PETSc options files"

but continued to be used for the PETSC_VIEWER_BINARY_MATLAB format
characters.  This prevented loading these files from PETSc.  This commit
switches to using '#' for those comment characters and updates
PetscReadBinaryMatlab to accept both '%$$ ' and '#$$ '.

Noticed-by: Richard Katz <richard.katz@earth.ox.ac.uk>
MatSetOption not always logically collective.

The PetscValidLogicalCollectiveBool(mat,flg,3) should not be
tested for non-logically collective op.
Fix computation of squared-norm in for the bt linesearch in the VIRS snes case
added start of Hands on tutorial that works through a few examples
bug fix for valgrind broadcasting uninitialized values
selected 4 tutorial examples began to cleanup tutorial page introduction on them
vis
Main page: Changed links to petsc-dev website
Makefile: Added TS ex11 to EXAMPLESC
TS ex11: Added some explanatory text. Need more.
TS ex11: Fixed docs
TS ex11: Added shallow water equations
HandsOn: Force Jed to come up with more exciting examples than these
HandsOn: update the run commands
HandsOn: update some runs
HandsOn: fix missing html format [from copy/paste]
added explanation of runs for HandsOnExercises
HandsOn: fix line numbers in URLs to ex*.c.html
HandsOn: rename all output files to .html - [to avoid popup on safari]
added <pre> to output files, added text to HandsOnTutorial.html
added ex42 example run commands
handson: update instructions [for ex42]