Options inconsistency

[Koc]

https://github.com/KnpLabs/KnpMenu/blob/master/doc/01-Basic-Menus.markdown#other-rendering-options Why some options is camelCased but other underscored?

[stof]

legacy. I would like to switch everything to underscores, but I'm not sure whether it is possible to provide a full BC layer, which is why I haven't done it everywhere

[shakaran]

Update link to documentation is https://github.com/KnpLabs/KnpMenu/blob/master/doc/01-Basic-Menus.md#other-rendering-options

Options affected are:

• - lastClass
• - firstClass
• - ancestorClass => PR Make ancestorClass option consistency to underscore #351
• - currentClass
• - currentAsLink
• - matchingDepth

I will make a separate pull request for each option updated. For avoid conflicts with master and each PR. It requires that will be accepted and merged to master one by one or I make a full PR with all the changes. I would prefer one by one, since it is more easy to follow the changes for maintainers. So waiting the approval of each merge one by one.