New IJulia approach
Added stuff for regular print
Pretty printing
Refactoring out printing stuff
Merge in new show
Variable and model printing redone, plus tests
Fix silly MathJax things
Merge pull request #98 from JuliaOpt/ijulia2

Re-organization of pretty printing, adds IJulia support
Speed tests still good
we already importall Base inside the module, these were not needed
fix warnings on master
tidy imports
remove support for deprecated Model(sense) constructor
fix #103
Heuristic callbacks
Docs and example for heuristic
Clarification over solver capabilities
Added extension capability, for robust split
fill var names for show call + printing refactor
method didn't exist