Added preliminary support to mark previous / next

[ax487]

There is one thing I badly miss form emacs multiple-cursors.el package, namely support for the operations mark previous like this and mark next like this, bound to ctrl-< and ctrl-> respectively.

I used these actions as a poor man's refactoring tools, i.e. to rename variables. I essentially select the variable name, mark all further occurences and rename the variable throughout a file / scope.

I added a simple snippet to add these features to your package. Please tell me what you think.

[kankaristo]

Sorry that it took me so long to take a look at this.

Looks like a valuable addition, and seems to be working well!

One thing I'd like to have is "Mark all like this", so you don't need to mash "Mark next like this". Do you think you could add that as well? I can also merge this as-is, and add that that later.

Any thoughts on "recommended" keybindings for these commands?