[fixed] Added support for building URLs with optional parameters

[dancannon]

You are now able to create links with optional parameters, before if you tried to do this the following error was returned Missing "param" parameter for path "/path/:param?".

Fixes some of the issues mentioned in #290.

[dancannon]

I should have mentioned above this PR is not yet complete but it adds some basic functionality.

[dancannon]

Ok I have added some more tests and I am now happy with the changed behaviour.

This should now be ready to go however since you mentioned in #290 that you were not sure if ? should be supported do you see any issues with adding this change?

[mjackson]

@dancannon This looks great!

@rpflorence What do you think? Can we keep ? ?

[th0r]

I'm for this PR with both hands! I have route catalog which looks like /catalog/:category?/:subcategory?. User can visit either /catalog, or /catalog/1 or catalog/1/2. Now I've separated catalog into 3 routes: catalog-root, catalog-category and catalog-subcategory, but generation of the navigation menu for them is a PAIN, because the name of the route depends on route params.
With optional params these 3 routes becomes one - catalog.

[tcoopman]

Would love to get this included!

For me the ? doesn't really matter, it's a bit more explicit but that's ok. Removing the ? is fine for me too.

[ryanflorence]

my only beef with ? was that you can't create links to it. this seems good.

If ? ends up causing other problems, and we're constantly fixing bugs in code around it, then I'll probably want to kill it again, but until then, this looks great :)

[mjackson]

Thanks @dancannon !

[dancannon]

Glad to help :)

[ryanflorence]

this is released on v0.9.4, thanks again!